Using the information provided, indicate which statistical test you think should be used for each of the following situations (a-d):

a.)Independent variable: normal birth weight vs. low birth weight infants; dependent variable: breathing rate (in breaths per minute).

b.)Independent variable: time of measurement of same patient (before and after surgery); dependent variable: heart rate.

c.)Independent variable: time of measurement (before, during, and after intervention); dependent variable: did vs did not exercise regularly.

d.)Independent variable: infertility treatment A vs infertility treatment B vs control condition; dependent variable: did vs did not become pregnant.