For each of the following scenarios or questions, say which method for hypothesis testing would be most appropriate to best answer the scientific question. Unless otherwise stated, make any necessary assumptions. Be as specific as possible. (Do not try to answer the biological question posed; just say what statistical technique would be best.)

a. Do Hospital A and Hospital B differ in the frequency of doctors who wash their hands before medical procedures?

b. Does the mean rate at which doctors wash their hands before medical procedures vary among the three hospitals X, Y, and Z?

c. Does the rate of hand washing at hospitals predict the proportion of patients catching infections?

d. Does washing hands for five minutes leave a different number of bacteria on people’s hands than washing for one minute, on average?

e. Which group washes hands for the greatest mean number of minutes each time, doctors or nurses?

f. Does whether or not doctors wash their hands before the first examination of patients have an effect on the lengths of patient stays in the hospital?

g. Do athletes have more mitochondria per muscle cell on average than nonathletes? (Assume that mitochondria per cell is normally distributed among individuals.)

h. Do athletes have a greater mean number of mitochondria per cell than nonathletes? (Assume that the number of mitochondria is not normally distributed but they have the same shape of distribution in the two groups.)

i. Is the mean number of mitochondria per cell in the muscles of people’s dominant arm different from the number in their other arm?

j. Is the proportion of males in an elephant population equal to 0.50?

k. Do two populations of elephants have the same proportion of males?

l. Are the left tusks of elephants on average longer than their right tusks?

m. Are elephants spread out over the savanna independently and with equal probability everywhere?

n. Is the length of elephants’ trunks normally distributed?

o. Are male elephants more variable in weight than are females?

p. Do male and female elephants differ in their mean growth rates? (Assume that elephant growth rate is not normally distributed but males and females have the same shape of distribution.)

q. Does the thickness of an elephant’s first left molar predict its age?

r. Does the thickness of an elephant’s first left molar predict whether it lives at least to 5 years of age?