Induction of labor and meconium staining. Meconium staining during childbirth may be a sign of fetal distress. A randomized trial was conducted to see whether induction of labor (by pitocin and other drugs delivered near term) would reduce the risk of meconium staining. The treatment group (n1 = 111) had elective inductions at 39 to 40 weeks of pregnancy. One delivery in the treatment group experienced meconium staining. In contrast, 13 of 117 pregnancies in the more conservatively managed group experienced meconium staining.q

(a) Determine the risks of meconium staining in each group.

(b) Even though the counts in table are small, can a Normal approximation (z-procedure) still be used to test the data? Show why.

(c) Conduct the hypothesis test using a z-procedure.

(d) Optional. Use a computer applet (e.g., www.OpenEpi.com) to calculate a P-value by Fisher’s exact test. Compare this P-value to the one derived from your z-procedure. How do they compare?