Risk factor for subsequent leukemia

A study examined the relationship between a mother having influenza during pregnancy and a subsequent diagnosis of leukemia or lymphoma in the child. The general design used cancer registry records to ascertain outcomes and birth certificates to record birth dates. Public health records of severe influenza seasons were also examined. Assigning children who were not in utero during a serious influenza season a risk ratio of 1.0, the researchers found the RR for children exposed during the first trimester was 3.5, during the second trimester it was 2.7, and during the third, it was 1.0.

a)  What are the stated null and alternative hypotheses?

b)  Describe the type of study design used.

c)  Overall, do you think the study design used was a good choice?  If yes, why?  If not, why not?

d)  How strongly can the researchers assert that a mother having influenza during pregnancy is a risk factor for subsequent leukemia or lymphoma diagnosis in the child?

e)  Describe how you might do the study using a design that is different from the one that the researchers used. Be sure to state your null and alternative hypotheses, source population, outcome, and exposure, and describe some strengths and weaknesses of your approach.  One or two