Random Effects Exercise
Respond to the following questions individually then discuss your answers in your group.
You should hand in your individual response. We will discuss your group responses and
then I will lecture on advanced topics.
1. Estimate variance components σ2
τand σ2from the following one-way random effects
ANOVA table:
Source df SS MS
Treatment 3 80 26.67
Error 24 120 5
Total 27 200 7.41
2. Run the SAS code for a two-way random effects model provided on the web page.
Copy the data provided into a Minitab worksheet and analyze the data using General
Linear Model under the ANOVA menu. Be sure to list both effects in the Random
Factors box and include the interaction in the model box (e.g., C1 C2 C1*C2).
(a) For which effects are SAS’s Type III tests correct? Which ones are incorrect?
(b) Do you know the SAS commands needed to compute the correct test statistics?
Add these command(s) to the SAS source code and compare SAS’s output to
Minitab’s GLM Model output.
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