A random sample is obtained from a population with a mean of = 45. After a

Question:

A random sample is obtained from a population with a mean of µ = 45. After a treatment is administered to the individuals in the sample, the sample mean is M = 49 with a standard deviation of σ = 12.
a. Assuming that the sample consists of n = 9 scores, compute r2 and the estimated Cohen's d
to measure the size of treatment effect.
b. Assuming that the sample consists of n = 16 scores, compute r2 and the estimated Cohen's d
to measure the size of treatment effect.
c. Comparing your answers from parts a and b, how does the number of scores in the sample influence the measures of effect size?