His example was great; just in depth enough to make it not super easy and straightforward, but difficult enough to help you actually learn and understand the steps carried out in an analysis of covariance. I am also glad he mentioned homogeneity of regression; this is a concept I sometimes forget or get confused about.
Thank you for the video Dr. Grande. I like how you showed the ANOVA and how the data changes when adding the covariate in the ANCOVA. This demonstration helped me understand the difference between the two tests.
Thank you very much Dr. Todd. I was able to learn your ANCOVA and used them for the statistical analysis for my manuscript. More power to your wonderful site...
Dr. Grande- Thank you for explaining the ANCOVA and how to run the analysis. Your interpretation of the analysis was clearly explained and highlighted in an intellectual way. This video allowed me to understand better between the differences of the test and controlling the covariates.
Great video. I appreciated the opportunity to reflect upon the differences and the similarities that can occur between ANCOVA and ANOVA. It also helped to explore how to use these analyses as well as what can be expected with regard to the results.
Thank you for the video. ANCOVA is a good tool to use that allows you to test the effects of treatment while controlling a covariate or something that could mediate the dependent variable.
Dr. Grande has drew a line in the sand between treatment and severity of treatment with this video. I can see clearer now. Good video. Concepts were really broken down nicely in this one.
Thank you! I appreciated your slower walk through in the beginning of this video rather than jumping right in to it. Helpful for us global thinkers to first see the big picture through an example.
This video explains clearly the rationale for using ANCOVA vs ANOVA tests which is very helpful. Testing for assumptions was nicely demonstrated as well.
I took from this video that there are a few assumptions that must be checked before running ANCOVA. There were alot of steps but Dr Grande does a good job explaining them all.
Thanks for the lesson. I would be be grateful if you could throw some light on 1. The assumption of normally distributed residuals for each category of the independent variable
There was a lot of information in this video. I was worried that ANCOVA was going to be difficult to understand. However, Dr. Grande broke it down very well. This will be a great video for me to refer back to in the future.
This video did a good job of showing how the ANOVA is connected to ANCOVA, and how the treatment affects depression levels. I never really thought about things like family support would be included in data analysis like this either.
Danielle Duboski I agree. Dr. Grande broke the concepts down, and he explained them in a way that was easy to understand. It was interesting to see how different variables in the study can be controlled for statistically.
This video does a great job showing the research design used to gather the data. Receiving the information before hand helps to understand the data calculations. I gather the ANOVA pertains to covariance's.
This video was great in allowing us to see the difference between treatment and depression level, and I would not have known that at that point you do not want significance.
This was helpful in understanding that ANCOVAs test the effect of a treatment while controlling for a covariate that may also affect the DV. To me, this seems extremely important in conducting accurate research and in understanding the results.
Jacklin Skibicki I agree. I never really thought about family support as being put into research. I knew if a person had it that they would do better with support, but it never occurred to me that it could be applied to data sets.
I have not used an ANCOVA before, actually prior to this class I do not think I had even heard the concept mentioned. I liked how the explanation of ANCOVA and covariant were explained thoroughly in regards to testing and effects on the variable.
This video was helpful in understanding the why and how of testing the assumptions for statistical significance and effect size. I understood the logic of controlling the covariates in order to determine whether the independent variable had an effect on the dependent variable. Seeing the results of both the ANOVA and ANCOVA solidifies the logic.
This video was extremely helpful in explaining how to run an ANCOVA. I needed to see this video, as I am sing ANCOVA for my research paper. I thought it was very clear in its instruction, and easy to understand.
I agree i thought this video was great in showing step by step instruction on how to run the ANCOVA. It was definitely useful in understanding and easy to follow.
Alright, that make more sense now seeing the ANOVA and ANCOVA back to back with the previous video. Seeing the differences in the make up of the two tests was helpful for understanding.
THis was pretty neat to see. ANCOVA allows one to control a co-varrient while finding the results of the data given. This simplifies the data and allows the study to have a result
So I will admit that I am a nerd and have a favortie statistical test and ANCOVA's are it. I think this video did a great job of explaining what an ANCOVA is and what it does. It's such a good test because it allows us to control for co-variates which is very useful!
Mandy Moore Agreed. I liked the straightforward explanation of what an ANCOVA tests for and how it is conducted. Certainly helpful in conducting research.
Putting this into a real-life example instead of just having numbers was extremely helpful with this one to understand the purposed of the ANCOVA. So this is used for testing the covariates you collected data on against your main variable(s) to see if it was affecting the results. I was left wondering what is a typical number of covariates and if I should consider adding them to my final paper.
Well, hey! Video for analysis of co-variance. An-Co-VA. That is literally all I needed to be able to understand this entire video. Within the first video, Dr. Grande explained what an ANCOVA is and what it does. This is what I wanted with all the other videos. Without that, I found it difficult to even comment on the content of the video because I didn't understand it on a basic level. I think this video was very good. I am able to see the difference between the treatment and severity of symptoms. I think it's cool that there is a test that can control for things that can alter your results in a test. What you can't control in real life, we can control for using the data.
Jessie Howard Yes, I agree, this one was very straight forward and I understood why the analysis was being run and how the result would be interpreted.
Jessie Howard Like you, I think I have been having trouble grasping the concepts because on a basic level I did not understand without a clear definition.
ANCOVA-takes into account the effects of a covariate. Covariate may have some influence on the DV. ANCOVA allows you to test the effect of a tx, while controlling for a covariate that could also have an effect on your DV. Got it!
you all probably dont give a shit but does someone know of a trick to get back into an Instagram account?? I somehow lost the password. I would love any tips you can give me!
@Colson Cory thanks so much for your reply. I found the site on google and Im in the hacking process atm. Seems to take quite some time so I will reply here later with my results.
I like the idea of running the ANOVA without the covariate first, and then Running the ANCOVA as a way to "see" the change that may or may not occur based on the Covariate that is helpful when interpreting results.
+Mark Vanderley This is intriguing! I will have to play around with it, but it would be interesting to see the interactions with and without the covariate.
I was happy to see how ANCOVA controlled for covariates. I think there was a lot of information in this video and although I feel like I took it in, I will probably refer back to this video a time or two to make sure I have it all down.
This video was easy to understand regarding the calculations. I have a hard time understanding the concept of the ANCOVA though. I know it counts for covariates but I do not understand how one calculation counts for all other variables. This was a great video and Dr. Grande explained this calculations great; I just think I should do more research on understanding what a ANCOVA actually is accounting for within a research study.
Brittany Vodzak I understand why we would control the covariant, but the calculations are not as easy to figure out. Part of the issue is my lack of SPSS.
This video cleared up some misunderstandings I had concerning IV, DV and CoVa. I think that the small effect that family support had on the outcome was interesting.
This data example helped me to have a better understanding of the role of the variation in the DV, it is not easy to know what to do with the extra variables that we don’t always want to examine in the study. The language the textbooks used is confusing, too many terms/steps. Thanks Dr. Grande, I appreciate your concrete/clear way to explain what an ANCOVA tests for and how it is conducted. Regarding the assumptions that need to be tested, ANCOVA have 2 assumptions in addition to the ones for ANOVA, right? So, you first test the ANOVAs and then the assumptions for ANCOVA? Also, the textbook listed a third assumption: The covariate is reliable and is measured without error. I guess, as with ANOVA, that is more a design issue that needs to be addressed before the data collection starts, right? Thanks again.
I really appreciated your explanation of how ANCOVA and ANOVA can be used together to provide valuable discussion and information. Can the ANCOVA be performed when the covariate is categorical rather than continuous? If not, what statistic can be utilized in that scenario? Thanks!
Thank you very much. Well what do we do if the difference between the dependent variable end the fixed factor IS significant. I have 3 groups of patients with significantly different age and want to adjust the analysis for this significant confounding factors. The parameters are mortality , dialysis initiation and evolution of renal function in time. Thank you so much in advance!!!
I understand the importance of ANCOVA in allowing you to test the treatment while controlling for a covariant but once assumptions are added in and different tables are shown it starts to get confusing.
Agreed, all the assumptions for all the tests get very confusing. However, ANCOVA"s are awesome for allowing us to control for co-variates to see if they have an afffect on the rest of the data.
Bethany Elstrom Bethany, I agree. Assumptions and tables are a bit intimidating but it's nice to walk through how to read the data (or what is most important to find in the data).
Bethany Elstrom I agree the visuals are kind of confusing. But I try to think of it in terms of words. What can get in the way of you seeing the true results of what you want? It's like "In a perfect world, all the people would be the same and we could truly see how X affects Y without the rest of the 24 letters" test. I think it's pretty cool. That is, if I understand it right.
Thanks for the useful video. I was wondering what to do when the first assumption shown in the video is violated (5:09)? a google search gives me different responses, and in Andy Field's book he only refers to a package called R when assumptions for ANCOVA are violated, but he doesn't explain what to do with it.
It was cool to learn how ANCOVA takes into account co-variate effects (co-variate being another variable that you measure that you think my influence the DV). If certain assumptions are met, you are able ot use ANCOVA to test the effect of treatment while controlling for a co-variate (hold one variable constant).
I think that it is great that there is a test that I can run to show the occurrence of covariance. I will be able to use this information in my paper since there are several factors that I am struggling to find controls for.
Dr. Grande, Thank you for your helpful videos. They are so well done and I have learned so much from them. I was hoping you could confirm or disconfirm a question that I am having trouble finding when accessing other resources. I know SPSS provides 2-tailed results for the classical t-test which need to be converted to communicate 1-tailed/directional results. What about the ANCOVA test? Does one not need to convert the results of an ANCOVA because it is an F test? Thank you for your help.
Great video I guess this is the only one that helps me around my problem that I am going to talk about..... I used mixed ANOCOVA in study and I not sure whether I am correct with interpretation. I had a 2X2X2 design with first two IVs as within and the last one as between (patient group vs healthy controls). There was a significant interraction between all three IVs before I ran the same analysis using a covariate which was basically scores on beck depression inventory. The same interraction turned out to be non significant when the covariate was introduced. I interrepreted that the covariate might be causing this interraction and thus "after controlling for scores on beck depression inventory this interraction was not significant." am I correct on that?
@5:46, the covariate you have is a numerical one. I have a categorical one. What assumptions need to be checked for a categorical variable as a covariate.
I actually didn't factor family support would be significant in the data analysis. I think of family support to be a factor but I didn't consider it to be a variable to test in research. This video is also helpful in understanding how ANCOVA test the effects of treatments for a covariate.
Thanks How many covariates can be tested by ANCOVA Is ANCOVA a suitable test for adjusting covariates when the sample size is small (40 cases over 2 comparative groups) ?
very helpful video thank u very much I want to know how to do a comparison of bone density between tow groups ( obese and non-obese) after stabilization of weight using ANCOVA test in SPSS and how interpret results as mean ± SD and significant diferrence between the two groups .. thanks
I have never used that program, so listening to it presently, I had no input. I can see myself coming back to this if/when I use this program because I am lost. It does not seem like something I cannot grasp, so that it good.
Because the significance was so similar, would the addition of the covariate be added in the write-up as adding little in the way of significance when compared to the ANOVA run with out it?
I am using an ANCOVA for my design but mine is a repeated measures ANCOVA. So beyond this analysis I need to determine what tests to run to insure no Type 1 error. Correct?
Thank you sir. Planning to use ANCOVA in my repeated-measures study with N=3 (with placebo treatment for each participant). Would it still be appropriate with extremely small sample size?
im running my data and i checked the effect of the covariate... it has significant difference. what should i do? since in the video, dr. todd said that findings should be no difference
If the data shows significance but a small effect size, would the research be considered successful? How important is effect size in terms of discussing what impact the variable may have on the DV?
I have just tested my data and there is a significant results when testing the covariate (the first step when you tested family support). What can I do now? I also tried with logged data and it was still significant
¡Exceptional explanation! By the way, ¿how to fix "Insufficient memory to execute this command" issue? This occurs only when I'm trying to carry out an ANCOVA. Please help me! Thanks in advance.
What do I do if I'm using a within-subjects decision? my supervisor told me to run the ANOVA but its' difficult testing the assumptions when all participants take part in each condition.
+Omar Hraib this was for my dissertation so after a long day of statistics reading I decided to run a repeated measures anova to compare the means of my dependent variable. Then I ran 4 hierarchal multiple regressions. Apparently it's very similar to running an ANCOVA but, this depends on your study and the previous literature
This video was very confusing for me to understand. I don't think I grasp ANCOVA as well as ANOVA. I want to say that I do understand what ANCOVA is used for and how to use it, but I cannot be 100% confident in that.
Susan Wilder I have to agree. I think ANCOVA is more detailed, but much more complex. I had a harder time understanding ANCOVA than I did ANOVA. I thought it was just be not understanding, but I am glad I'm not the only one that thought it was more complex.
He says, "if you're looking to demonstrate that 12 weeks duration is more effective than 6 weeks, you can reject the null, there's no difference between the groups, which is likely the objective." This is incorrect! 1) if you REJECT the null, then there IS a difference between the groups! This is a crucial mistake in anyone watching this trying to learn. 2) you are never aiming to not find a difference. 3) the P value clearly states there is a difference between the groups.
You may have misheard me. I said "you can reject the null, that there's no difference between the groups, which, in a design like this, is likely the objective." Meaning the null hypothesis states that there is no difference between the groups.
His example was great; just in depth enough to make it not super easy and straightforward, but difficult enough to help you actually learn and understand the steps carried out in an analysis of covariance. I am also glad he mentioned homogeneity of regression; this is a concept I sometimes forget or get confused about.
Thank you for the video Dr. Grande. I like how you showed the ANOVA and how the data changes when adding the covariate in the ANCOVA. This demonstration helped me understand the difference between the two tests.
Thank you very much Dr. Todd. I was able to learn your ANCOVA and used them for the statistical analysis for my manuscript. More power to your wonderful site...
Dr. Grande- Thank you for explaining the ANCOVA and how to run the analysis. Your interpretation of the analysis was clearly explained and highlighted in an intellectual way. This video allowed me to understand better between the differences of the test and controlling the covariates.
This presentation proved to be very clarifying. I appreciate the testing for assumptions; makes the process easier to comprehend.
Great video. I appreciated the opportunity to reflect upon the differences and the similarities that can occur between ANCOVA and ANOVA. It also helped to explore how to use these analyses as well as what can be expected with regard to the results.
Thank you for the video. ANCOVA is a good tool to use that allows you to test the effects of treatment while controlling a covariate or something that could mediate the dependent variable.
This video was great at explaining that controlling for co-variates is really important, how to do this, and what assumptions have to be met first.
Dr. Grande has drew a line in the sand between treatment and severity of treatment with this video. I can see clearer now. Good video. Concepts were really broken down nicely in this one.
Thank you! I appreciated your slower walk through in the beginning of this video rather than jumping right in to it. Helpful for us global thinkers to first see the big picture through an example.
This video explains clearly the rationale for using ANCOVA vs ANOVA tests which is very helpful. Testing for assumptions was nicely demonstrated as well.
I took from this video that there are a few assumptions that must be checked before running ANCOVA. There were alot of steps but Dr Grande does a good job explaining them all.
I agree that the video was easy to follow.
Very easy video to follow. As Ivy said, running the data without the covariate helped me understand this analysis better.
Thanks for the lesson. I would be be grateful if you could throw some light on
1. The assumption of normally distributed residuals for each category of the independent variable
There was a lot of information in this video. I was worried that ANCOVA was going to be difficult to understand. However, Dr. Grande broke it down very well. This will be a great video for me to refer back to in the future.
This video did a good job of showing how the ANOVA is connected to ANCOVA, and how the treatment affects depression levels. I never really thought about things like family support would be included in data analysis like this either.
Danielle Duboski I agree. Dr. Grande broke the concepts down, and he explained them in a way that was easy to understand. It was interesting to see how different variables in the study can be controlled for statistically.
Thanks, Dr G. It was really helpful to see the use of the ANOVA as part of the ANCOVA.
This video does a great job showing the research design used to gather the data. Receiving the information before hand helps to understand the data calculations. I gather the ANOVA pertains to covariance's.
***** I would have never thought that the only difference between the two is the covariance measurement.
This video was very informative in explaining how ANCOVA works as far as controlling the co-variates.
Showing results from the same data set with ANOVA and ANCOVA was helpful. It was clear how to walk through this, step-by-step, with my data.
This video was great in allowing us to see the difference between treatment and depression level, and I would not have known that at that point you do not want significance.
Candace Fernandez Yes, agreed!
Candace Fernandez same, would not have know if not for this video!
This was helpful in understanding that ANCOVAs test the effect of a treatment while controlling for a covariate that may also affect the DV. To me, this seems extremely important in conducting accurate research and in understanding the results.
Jacklin Skibicki I agree. I never really thought about family support as being put into research. I knew if a person had it that they would do better with support, but it never occurred to me that it could be applied to data sets.
I have not used an ANCOVA before, actually prior to this class I do not think I had even heard the concept mentioned. I liked how the explanation of ANCOVA and covariant were explained thoroughly in regards to testing and effects on the variable.
Chelsey Davis This is the first time I have heard of it too. However, Dr. Grande provided an awesome explanation regarding ANOVA and its importance.
This video was helpful in understanding the why and how of testing the assumptions for statistical significance and effect size. I understood the logic of controlling the covariates in order to determine whether the independent variable had an effect on the dependent variable. Seeing the results of both the ANOVA and ANCOVA solidifies the logic.
It was helpful to see the process of how to test the assumptions. I also appreciated the tip about running the data first without the covariate.
This video was extremely helpful in explaining how to run an ANCOVA. I needed to see this video, as I am sing ANCOVA for my research paper. I thought it was very clear in its instruction, and easy to understand.
I agree i thought this video was great in showing step by step instruction on how to run the ANCOVA. It was definitely useful in understanding and easy to follow.
There are still some terms that I was confused about, but overall it helps that Dr. Grande was able explain this video step by step.
Alright, that make more sense now seeing the ANOVA and ANCOVA back to back with the previous video. Seeing the differences in the make up of the two tests was helpful for understanding.
THis was pretty neat to see. ANCOVA allows one to control a co-varrient while finding the results of the data given. This simplifies the data and allows the study to have a result
So I will admit that I am a nerd and have a favortie statistical test and ANCOVA's are it. I think this video did a great job of explaining what an ANCOVA is and what it does. It's such a good test because it allows us to control for co-variates which is very useful!
Mandy Moore Agreed. I liked the straightforward explanation of what an ANCOVA tests for and how it is conducted. Certainly helpful in conducting research.
Putting this into a real-life example instead of just having numbers was extremely helpful with this one to understand the purposed of the ANCOVA. So this is used for testing the covariates you collected data on against your main variable(s) to see if it was affecting the results. I was left wondering what is a typical number of covariates and if I should consider adding them to my final paper.
Well, hey! Video for analysis of co-variance. An-Co-VA. That is literally all I needed to be able to understand this entire video. Within the first video, Dr. Grande explained what an ANCOVA is and what it does. This is what I wanted with all the other videos. Without that, I found it difficult to even comment on the content of the video because I didn't understand it on a basic level. I think this video was very good. I am able to see the difference between the treatment and severity of symptoms. I think it's cool that there is a test that can control for things that can alter your results in a test. What you can't control in real life, we can control for using the data.
Jessie Howard Yes, I agree, this one was very straight forward and I understood why the analysis was being run and how the result would be interpreted.
I felt the same way watching this. I need to be able to understand the basic concept of each lesson first and then I am pretty okay after that.
Jessie Howard An-Co-Va...it does seem easy to understand now that I know what ANCOVA means!
Jessie Howard Like you, I think I have been having trouble grasping the concepts because on a basic level I did not understand without a clear definition.
Danielle Maldonado Yes, having a clear definition does make things better to understand. I think makes it all sink in a little bit more.
ANCOVA-takes into account the effects of a covariate. Covariate may have some influence on the DV. ANCOVA allows you to test the effect of a tx, while controlling for a covariate that could also have an effect on your DV. Got it!
you all probably dont give a shit but does someone know of a trick to get back into an Instagram account??
I somehow lost the password. I would love any tips you can give me!
@Zain Kendrick instablaster ;)
@Colson Cory thanks so much for your reply. I found the site on google and Im in the hacking process atm.
Seems to take quite some time so I will reply here later with my results.
@Colson Cory it worked and I finally got access to my account again. Im so happy:D
Thanks so much you saved my account :D
@Zain Kendrick you are welcome xD
I like the idea of running the ANOVA without the covariate first, and then Running the ANCOVA as a way to "see" the change that may or may not occur based on the Covariate that is helpful when interpreting results.
+Mark Vanderley This is intriguing! I will have to play around with it, but it would be interesting to see the interactions with and without the covariate.
+Mark Vanderley I agree, I think that helps the researcher conceptualize the level of impact the covariate has.
Great Great Video on how to conduct ANCOVA simple but meaningful
Fantastic explanation. Thank you Doctor
thank you for saving my thesis dr. grande!
I was happy to see how ANCOVA controlled for covariates. I think there was a lot of information in this video and although I feel like I took it in, I will probably refer back to this video a time or two to make sure I have it all down.
Dr. Grande you are my favorit
This video was easy to understand regarding the calculations. I have a hard time understanding the concept of the ANCOVA though. I know it counts for covariates but I do not understand how one calculation counts for all other variables. This was a great video and Dr. Grande explained this calculations great; I just think I should do more research on understanding what a ANCOVA actually is accounting for within a research study.
Brittany Vodzak I understand why we would control the covariant, but the calculations are not as easy to figure out. Part of the issue is my lack of SPSS.
Thank you so much for this video, Dr. Grande. It helped me a lot!
Very helpful to see the assumptions tested.
Very good & easy explanation! Exactly what I was looking for
This video cleared up some misunderstandings I had concerning IV, DV and CoVa. I think that the small effect that family support had on the outcome was interesting.
I agree with you Kara, this video was useful and very easy to follow
Me too Kara. It seems like we all had some of the same questions that needed clarification. This video helped many of us.
I like that you can control for things like family factors with the Ancova
Katherine Beck That really interested me as well and being able to see how the duration can effect the significance.
Thank you for this video! It helped me make it through my homework!
This data example helped me to have a better understanding of the role of the variation in the DV, it is not easy to know what to do with the extra variables that we don’t always want to examine in the study. The language the textbooks used is confusing, too many terms/steps. Thanks Dr. Grande, I appreciate your concrete/clear way to explain what an ANCOVA tests for and how it is conducted.
Regarding the assumptions that need to be tested, ANCOVA have 2 assumptions in addition to the ones for ANOVA, right? So, you first test the ANOVAs and then the assumptions for ANCOVA? Also, the textbook listed a third assumption: The covariate is reliable and is measured without error. I guess, as with ANOVA, that is more a design issue that needs to be addressed before the data collection starts, right? Thanks again.
This video was very helpful and also surprisingly easy to follow
It's funny because this is the first video I feel I might just understand.
I like that you can control variables then see the difference for treatment on dependent variables.
I really appreciated your explanation of how ANCOVA and ANOVA can be used together to provide valuable discussion and information. Can the ANCOVA be performed when the covariate is categorical rather than continuous? If not, what statistic can be utilized in that scenario? Thanks!
it's wonderful to have this ! thanks
Very helpful video. Easy to follow as well.
This has helped me so much. Thank you!
Thank you very much. Well what do we do if the difference between the dependent variable end the fixed factor IS significant. I have 3 groups of patients with significantly different age and want to adjust the analysis for this significant confounding factors. The parameters are mortality , dialysis initiation and evolution of renal function in time. Thank you so much in advance!!!
I understand the importance of ANCOVA in allowing you to test the treatment while controlling for a covariant but once assumptions are added in and different tables are shown it starts to get confusing.
Agreed, all the assumptions for all the tests get very confusing. However, ANCOVA"s are awesome for allowing us to control for co-variates to see if they have an afffect on the rest of the data.
Bethany Elstrom I agree
Bethany Elstrom Bethany, I agree. Assumptions and tables are a bit intimidating but it's nice to walk through how to read the data (or what is most important to find in the data).
Bethany Elstrom I agree the visuals are kind of confusing. But I try to think of it in terms of words. What can get in the way of you seeing the true results of what you want? It's like "In a perfect world, all the people would be the same and we could truly see how X affects Y without the rest of the 24 letters" test. I think it's pretty cool. That is, if I understand it right.
Great video. Thanks Todd.
Thanks for the useful video. I was wondering what to do when the first assumption shown in the video is violated (5:09)? a google search gives me different responses, and in Andy Field's book he only refers to a package called R when assumptions for ANCOVA are violated, but he doesn't explain what to do with it.
It was cool to learn how ANCOVA takes into account co-variate effects (co-variate being another variable that you measure that you think my influence the DV). If certain assumptions are met, you are able ot use ANCOVA to test the effect of treatment while controlling for a co-variate (hold one variable constant).
Very helpful explanation of it.
This was extremely helpful. Thank you!
You are welcome - thank you for watching -
I think that it is great that there is a test that I can run to show the occurrence of covariance. I will be able to use this information in my paper since there are several factors that I am struggling to find controls for.
Melissa Clendaniel I will admit...it made me do a little dance inside when I found out what an ANCOVA does.
Dr. Grande,
Thank you for your helpful videos. They are so well done and I have learned so much from them. I was hoping you could confirm or disconfirm a question that I am having trouble finding when accessing other resources. I know SPSS provides 2-tailed results for the classical t-test which need to be converted to communicate 1-tailed/directional results. What about the ANCOVA test? Does one not need to convert the results of an ANCOVA because it is an F test? Thank you for your help.
does the covariate always needs to be in continuous variable or can it be in ordinal variable?
Great video I guess this is the only one that helps me around my problem that I am going to talk about..... I used mixed ANOCOVA in study and I not sure whether I am correct with interpretation.
I had a 2X2X2 design with first two IVs as within and the last one as between (patient group vs healthy controls). There was a significant interraction between all three IVs before I ran the same analysis using a covariate which was basically scores on beck depression inventory. The same interraction turned out to be non significant when the covariate was introduced.
I interrepreted that the covariate might be causing this interraction and thus "after controlling for scores on beck depression inventory this interraction was not significant."
am I correct on that?
This is amazing! Thank you so much!
Informative - thank you!
@5:46, the covariate you have is a numerical one. I have a categorical one. What assumptions need to be checked for a categorical variable as a covariate.
Very clear. Thank you!
I actually didn't factor family support would be significant in the data analysis. I think of family support to be a factor but I didn't consider it to be a variable to test in research. This video is also helpful in understanding how ANCOVA test the effects of treatments for a covariate.
Jasmine Aviles yes, good point. covariates can be a lot of different things.
Very good video.
Very nice sir
Thanks
How many covariates can be tested by ANCOVA
Is ANCOVA a suitable test for adjusting covariates when the sample size is small (40 cases over 2 comparative groups) ?
very helpful video thank u very much
I want to know how to do a comparison of bone density between tow groups ( obese and non-obese) after stabilization of weight using ANCOVA test in SPSS and how interpret results as mean ± SD and significant diferrence between the two groups .. thanks
The significance of family support is 0.731. What does it mean? Does it mean that covariate is significantly related to dependent variable?
I have never used that program, so listening to it presently, I had no input. I can see myself coming back to this if/when I use this program because I am lost. It does not seem like something I cannot grasp, so that it good.
Because the significance was so similar, would the addition of the covariate be added in the write-up as adding little in the way of significance when compared to the ANOVA run with out it?
I am using an ANCOVA for my design but mine is a repeated measures ANCOVA. So beyond this analysis I need to determine what tests to run to insure no Type 1 error. Correct?
Thank you sir. Planning to use ANCOVA in my repeated-measures study with N=3 (with placebo treatment for each participant). Would it still be appropriate with extremely small sample size?
im running my data and i checked the effect of the covariate... it has significant difference. what should i do? since in the video, dr. todd said that findings should be no difference
If the data shows significance but a small effect size, would the research be considered successful? How important is effect size in terms of discussing what impact the variable may have on the DV?
+Elizabeth Adair Effect size is of particular importance because it indicates how much variance in the DV is explained by the IV.
I have just tested my data and there is a significant results when testing the covariate (the first step when you tested family support). What can I do now? I also tried with logged data and it was still significant
what if the assumption of homogeneity of regression slopes is violated?
¡Exceptional explanation! By the way, ¿how to fix "Insufficient memory to execute this command" issue? This occurs only when I'm trying to carry out an ANCOVA. Please help me!
Thanks in advance.
What do I do if I'm using a within-subjects decision? my supervisor told me to run the ANOVA but its' difficult testing the assumptions when all participants take part in each condition.
+Omar Hraib this was for my dissertation so after a long day of statistics reading I decided to run a repeated measures anova to compare the means of my dependent variable. Then I ran 4 hierarchal multiple regressions. Apparently it's very similar to running an ANCOVA but, this depends on your study and the previous literature
This video was very confusing for me to understand. I don't think I grasp ANCOVA as well as ANOVA. I want to say that I do understand what ANCOVA is used for and how to use it, but I cannot be 100% confident in that.
Could someone explain, if ANCOVA can be used if I have both pre and post-test variables
Same question
I need this data set
An ACOVA is more complex than an ANOVA and factors in that it factors in covariates.
Susan Wilder I have to agree. I think ANCOVA is more detailed, but much more complex. I had a harder time understanding ANCOVA than I did ANOVA. I thought it was just be not understanding, but I am glad I'm not the only one that thought it was more complex.
Plz provide me this data set
He says, "if you're looking to demonstrate that 12 weeks duration is more effective than 6 weeks, you can reject the null, there's no difference between the groups, which is likely the objective." This is incorrect! 1) if you REJECT the null, then there IS a difference between the groups! This is a crucial mistake in anyone watching this trying to learn. 2) you are never aiming to not find a difference. 3) the P value clearly states there is a difference between the groups.
You may have misheard me. I said "you can reject the null, that there's no difference between the groups, which, in a design like this, is likely the objective." Meaning the null hypothesis states that there is no difference between the groups.