A research would like to examine the effects of humidity on eating behavior. It is known that laboratory rats normally eat an average of µ = 21 grams of food each day. The research selects a random sample of n = 16 rats and places them in a controlled atmosphere room in which the relative humidity is maintained at 90%. The daily food consumption scores for rats are as follows:
14, 18, 21, 15, 18, 18, 21, 18
16, 20, 17, 19, 20, 17, 17, 19
a. Can the researcher conclude that humidity has a significant effect on eating behavior? Use a two-tail test with  = .05.
b. Compute the estimated Cohen's d and r 2 to measure the size of the treatment effect.
The solution provides step by step method for the calculation of testing of hypothesis, Cohen's d and effect size. Formula for the calculation and Interpretations of the results are also included.