Question: A researcher would like to examine the effects of humidity on eating behavior. It is know that laboratory rats normally eat an average of µ= 21 grams of food each day. The researcher selects a random sample of n=100 rats and places them in controlled atmosphere room where the relative humidity is maintained at 90%. The daily food consumption for the sample averages M=18.7 with SS = 2475.

a. Can the researcher conclude that humidity has a significant effect on eating?

behavior? Use a two-tailed test with α= .05.

b. Compute the estimated d and r² to measure the size of the treatment effect.