Pretest and Posttest Analysis with ANCOVA and Repeated Measures ANOVA using SPSS
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- Опубликовано: 6 июл 2024
- This video demonstrates how to analysis pretest and posttest data using SPSS when there is both a between-subjects factor and a within-subjects factor. Two methods for analyzing these data will be reviewed: Analysis of Covariance (ANCOVA) and Repeated Measures Analysis of Variance (RM ANOVA).
Dr. Grande's videos are a lot easier to understand than reading in a book. I tried several online sources and book sources and Dr. Grande did the trick. Thank you!
I took an interest in this video after we spoke in class about between-subjects and within-subjects anova. this video continued my understanding and cleared some of the confusions i had. thank you
This video is easier to follow and understand, and especially when conducting pretest and post-test analysis
I am using this data in an upcoming research proposal, this is very useful in furthering my understanding regarding variables in pretest and posttest.
Thank you! Great help. Easy to follow and understand!
Thanks for this video @Dr. Todd Grande
In my dataset, it seems that I may need to use a non-parametric version of ANCOVA since I am getting a significance of greater than 0.05 in the Levene's Test of Equality of Error Variances. Any suggestions on which tests I can use instead of ANCOVA?
I can appreciate this video because it made things clearer for me. I understand how analyzing the pre-test and post-test can be beneficial and the difference between the ANCOVA AND ANOVA. I have to say that I was confused when it came to the sphericity and it's importance in this example.
This video cleared it up for me too. I also had some trouble differentiating between ANCOVA and ANOVA.
I also had difficulty understanding the differences between these two measures before watching the video. It definitely helped me to choose one over the other for my research proposal and justify why I chose the one I did!
Your videos saved my life
Thank you so much Dr. Grande for your amazing videos.
Dr. Grande, I am still confused about what would fit with my research. I have a study of 40 participants and two treatment groups taking three different tests at three time points (pre-, post-, delayed) and these tests were graded by three raters on a scale comprised on two sections; namely; content and form and at the end overall score is provided.
Half of participants worked in one treatment while the other half was assigned to the other treatment. I initially conducted 2 x 2 ANOVA for analysing the students’ overall within and between subjects effects looking at performance at the three tests (pre-test, post-test and delayed test) and everything was fine. However, I found that the two groups are not equivalent at the pre-testing stage (baseline) even though they were randomly assigned, so I was advised to use ANCOVA instead. So would you please help me get an answer to the following concerns:
1. In my research, I want to see whether there were differences between the participants’ overall writing performance at the different time points
2. I also want to check for any differences in the writing performance in areas of form/content between the two groups.
3. I also would like to look to ( within subject effects) whether there were differences in the improvement in the form/content areas in the two treatments.
4. I also want to check for any within participants’ effects in the overall writing performance at the different time points.
Please help me and provide me with guidance on this matter.
Particularly, What type of ANCOVA should I use; Should I use one-way ANCOVA, two-way ANCOVA or Repeated measures ANCOVA.
Many thanks and God bless you.
Is there a way to analyze data in SPSS that involves several pre and posts tests for the same treatment group? For example body temperature before and after exercise in 5 trials.
Thank you. I've been struggling with trying what to write for fake research proposal for hours
The first part of the video did a good job of breaking down the steps involved for the pre and post test analysis. However, I got lost with the multivariate portion. Will have to explore this topic further.
Thank you so much for your instruction video. It is really useful and help me analyzing my data. May I ask you one more question? What to do if there are drop out cases? Do I have to adjust the data in case the number of participant is different between control and treatment group at the follow up phase. Looking forward to hearing from you.
Thank you for the informative video. While performing repeated measure ANOVA at 3 time points for a variable, I have found that the Multivariate table showed non significance but assuming sphericity, the within subject table showed significance. If you can help me how to interpret that and which table to look into for conclusion?
Thanks! dr. Grande!
Dear Todd, how can we do the same procedure with structural equation modeling, especially with AMOS?
If you have several different pre/post scores such as depression, anxiety and stress do you run separate ANOVAs?
Very useful, thank you very much.
You're welcome!
In my research I have two treatment groups and in each group I have taken measurements of pressure at 3 intervals ie 0, 2, 4, 8 weeks. I want to compare significance between 2 groups. Which test to use? How to say which treatment is better than other?
what if we have only one group and make 3 repetition with no treatment, then 3 repetition with treatment. (within group i mean). i couldnt find any source for this and i simply made a paired t test with each participant's avg. results. but im not sure if that's scientific.
I've followed your instructions in wilcoxon, paired t-test, independent t test and anova, and these things. I don't know which one is correct in analyzing the difference between the pretest and posttest if the number of participants in my control group is 15 and control group is also 15, defying the criteria of using parametric test. What should I do? Please help♥️😭
I have a question. I am analysing data from three different groups of participants for pre and post test perceptions after a training. I want to use repeated measures anova but i have only two time points- time1 and time 2. How do I check for sphericity of assumption with only two time points?
When there are only two time points, then sphericity is assumed. That's why you don't see a significance value in the relevant SPSS box when there are two time points. It's only when there are 3 times points that you have to look for sphericity.
what ccan be the research question for the ANCOVA one ?
Thaks for information
You're welcome -
Dr grande would you care to make a video of repeated measure ANCOVA with two fixed effects treatment and time, one or two covariates and a between subject factor called length between treatments which varies between subjects? Also I would appreciate if you can start with model formulations.
Sir also explain between group comparison in results of this video