case1302 {Sleuth2} | R Documentation |
One company of soldiers in each of 10 platoons was assigned to a Pygmalion treatment group, with remaining companies in the platoon assigned to a control group. Leaders of the Pygmalion platoons were told their soldiers had done particularly well on a battery of tests which were, in fact, non-existent. In this randomised block experiment, platoons are experimental units, companies are blocks, and average Practical Specialty test score for soldiers in a platoon is the response. The researchers wished to see if the platoon response was affected by the artificially-induced expectations of the platoon leader.
case1302
A data frame with 29 observations on the following 3 variables.
Company
"C1"
, "C2"
, ..., "C10"
Treat
"Pygmalion"
and "Control"
Score
Ramsey, F.L. and Schafer, D.W. (2002). The Statistical Sleuth: A Course in Methods of Data Analysis (2nd ed), Duxbury.
Eden, D. (1990). Pygmalion Without Interpersonal Contrast Effects: Whole Groups Gain from Raising Manager Expectations, Journal of Applied Psychology 75(4): 395–398.
str(case1302) # two-way model with interactions fitfull <- aov(Score ~ Company*Treat, case1302) # No problems are indicated by residual plot plot(fitfull) # Interaction terms are not statistically significant anova(fitfull) # Additive model, with "treatment contrast" for treatment: fitadditive <- aov(Score ~ Company + Treat, case1302) # Interpret treatment effect as coefficient of Treat anova(fitadditive)