Two Way ANOVA - SPSS (part 1)

I perform and interpret a two way ANOVA in SPSS. The example consists of 2 between subjects factors: one with 2 levels and one with 3 levels. So, it's a 2 * 3 between subjects design. I test both main effects and the interaction effect. I then follow-up with some basic post-hoc tests. I point out that the proper way to test the simple main effects for the interaction can only be achieved by adding a term to the syntax, as it can not be done through the menus. Also, this example is based on unbalanced design. That is, the sample sizes are unequal. This has important implications for factorial anovas, as I demonstrate through comparisons between the means reported in the descriptives table versus the means reported in the 'estimated marginal means' table.

The references I mention in the video are:

Keselman, H. J. Games, P. A., & Rogan, J. C. (1979). Protecting the overall rate of Type I errors for pairwise comparisons with an omnibus test statistic. Psychological Bulletin, 6(4), 884-888.

Keppel, G. (1982). Design and analysis: A researcher's handbook. New Jersey: Prentice Hall.

Howell, D. C. & McConaughy, S. H. (1982). Nonorthogonal analysis of variance: Putting the question before the answer. Educational and Psychological Measurement, 42, 9-24.

[jeremybfield]

Thank you so much, your tutorials are so much more helpful than those provided by my school.

[chongyeeyin]

All I want to say is your step by step explanation was excellent.

[classthenvironmentalscie]

very much helpful application and interesting lectures for learning spss

[saadalhumaid]

This guy is a master in statistics and spss

[JustMeTimbo]

It's funny how the number of watches keeps decreasing from 1-8 and then again increases as if people wanted to hear a conclusion.

THANK YOU for this tutorial!

[jbergonz]

Thanks very much for the video, very well explained. I enjoyed every detail, even when you burp at 2:16.

[chalidachai.]

Thank for this video. very well explained.

[mrszaraxox]

What should you use if you have multiple dependent variables you want to analyse if you can only put one dependant variable at a time with this model? My third year research product is proving to be very hard!

[Mock_immorality]

Hi there, thanks for this. But what if one has two IVs that are Scale and a group variable that's both dichotomous and nominal? Does that work? Eg Group where 1 = Control and 2 = Motor impaired. Then the two IVs are both reaction times?

[dr.jefferyelormakortiaagbe]

i have a data which i generated using wound size from day 0 to day 15 to 3 different treatment regimes as a measure of wound contraction how do i analyze this data with anova

[Ronnet]

Hi, maybe someone can help me out. I have a similar dataset to the case in the video. I have a performance measure (scale data) as my dependent variable. I also have gender (nominal) as one of the independent variables. However, a 'situation' variable (nominal). Basically my dataset includes every person is twice, perfoming in two different situations.

So I could use a paired sample t-test if I want to check the main effect of situation on performance for each person. And I could use an independent t-test to check the main effect of gender on performance.

However, how can I check for potential interaction effects? Which test to use? Two way ANOVA seems not applicable since my sample is not independent but gender is independent.

[zhubo]

First, I would like to thank you for this great Job. I have a problem on how to arrange my data, I have two factors (Agricultural sediment and urban sediment), then 15 plant species, and biomass (dry weight, fresh weight, etc). So, I would like to know using two way ANOVA, what could be gender, jobcat and salary? I have tried with agricultural sediment (level 1) and urban sediment (level 2); Jobcat "[15 species( with 3 replicates) in each factor), then salary ( biomass value), but it doenst work. Thank you in advance.

[avaphillips]

Hi, I wondered if you could help me...
I conducted a study that had 1 IV (with three levels/conditions) and then looked at the effect of the levels on decreasing symptoms over a 5 year period - looking at beginning point and end point. I wanted to find out if there was a difference between the three conditions on how much they decrease symptoms from point a to b. 
What test would I use?
I think that it would be a 2x3 way anova, followed by post hoc followed by independent samples t test?
Would appreciate your advice! Thanks 

[DontClarify]

What am I doing wrong if I wont show me the interaction effect in the option and therefore I dont get interaction effects in the output???

[asilasil]

Plz when I use 2way anova, I have to compute sum or mean?

If I have stress scale q1...q10

I have to copmute stress mean or sum and then apply 2way anova?

Thank you

[ditmerk]

How do you display means in the newest SPSS?

Awesome vids btw. i have used them a lot

[davidge]

Hi there, i conducted a study with 2 effect groups (water and land) and one control group. Results from each group were recorded pre-test and every week after this for three weeks (4 sets of results). Which statistical test would i run for this? I believe it would be a two way ANOVA but i am unsure. Thanks.

[linanina]

Hi, plz could u help me. I conducted a study with just one group (experimental group) with 10 individual. Results for each individual is recorded pre test and post test, (classroom treatment is not recorded) .which statistical test can fit my study??

[TheMaimizo]

What are your thoughts on SPSS in terms of analysis of categorical variables. I know from experience that it is good practice to code factors as alpha numeric in R as to not get nonsensical analysis using linear models. How is it in SPSS? I guess since you put the factor variable into "factor" it doesn't really matter. I guess the point I am trying to make what are the pitfalls of data coding and inference testing

[arigvi]

Do you need to include the control in your two way ANOVA? Specifically the positive control? It would really help if you answer :D