For each of the following scenarios, state what statistic would be used to estimate the effect of interest.

a. How different are the two hospitals X and Y in the frequency of doctors who wash and do not wash their hands before medical procedures?

b. How different is the number of bacteria on hands between people who wash for one minute and people who do not wash their hands?

c. How different are athletes and nonathletes in the mean number of mitochondria per muscle cell?

d. How different is the number of mitochondria per cell between the muscles of people’s dominant arm and the muscles in their other arm?

e. What fraction of individuals in an elephant population are male?

f. How different are the frequencies of males in two populations of elephants?

g. How much variation in weight is there among individuals in an elephant population?

h. How strong is the association between the number of mitochondria per cell in arm muscles and leg muscles?