1. A manufacturer of infant formula is running an experiment using the standard (control) formula, and two new formulas, A and B. The goal is to boost the immune system in infants. 120 infants in the study are randomly assigned to each of three groups: group A, group B, and a control group. There are 40 infants per group, and the study is run for 12 weeks. At the end of the study the variable measured is total IGA (in mg per dl), with higher values being more desirable. We are going to run a one-way ANOVA on these data. The hypotheses tested by the one-way ANOVA F test are
A. H0: the mean IGA score is the same for all three formulas.
Ha: the mean IGA score is higher for both treatment groups A and B than the control group.
B. H0: the mean IGA score is the same for all three formulas.
Ha: the mean IGA score is higher for at least one of the two treatment groups than the control group.
C. H0: the mean IGA score is the same for all three formulas.
Ha: the mean IGA score is not the same for all three formulas.
2. A researcher is studying treatments for agorophobia with panic disorder. The treatments are to be the drug Imipramine at the doses 1.5 mg per kg of body weight and 2.5 mg per kg of body weight. There will also be a control group given a placebo. Thirty patients were randomly divided into three groups of 10 each. One group was assigned to the control, and the other two groups were assigned to each of the two treatments. After 24 weeks of treatment, each of the subject's symptoms were evaluated through a battery of psychological tests, where high scores indicate a lessening of symptoms. Assume the data for the three groups are independent and the data are approximately Normal. The means and standard deviations of the test scores for the three groups are given below.
The P-value of the ANOVA F test is
A. greater than 0.10.
B. between 0.05 and 0.10.
C. below 0.05.