Question: . A researcher would like to examine the effects of humidity on eating behavior. It is known that laboratory rats normally eat an average of u=21 grams of food each day. The researcher selects a random sample of n=100 rats and places them in a 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 a=.05.

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