A recent study examined the link between miscarriage and the use of painkillers during pregnancy. Scientists interviewed 1009 women soon after they got positive results from pregnancy tests about their use of painkillers around the time of conception or in the early weeks of pregnancy. The researchers then recorded which of the pregnancies were successfully carried to term. The results are inTable 2.10.

(a) What percent of the pregnancies ended in miscarriage?
(b) Compute the percent of miscarriages for each of the four groups. Discuss the results.
(c) Is this an experiment or an observational study? Describe how confounding variables might affect the results.
(d) Aspirin and ibuprofen belong to a class of medications called nonsteroidal anti-inflammatory drugs, or NSAIDs. What percent of women taking NSAIDs miscarried? Does the use of NSAIDs appear to increase the risk of miscarrying? Does the use of acetominophen appear to increase the risk? What advice would you give pregnant women?
(e) Is Table 2.10 a two-way table? If not, construct one for these data.
(f) What percent of all women who miscarried had taken no painkillers?

Total Miscarriage Aspirin 5 22 53 172 Ibuprofen Acetaminophen No painkiller Total 13 24 103 762 1009 145