Question

La Leche League International reports that the mean age of weaning a child from breastfeeding is much later worldwide than it is in the United States. Suppose a random survey is conducted of 37 U.S. mothers who recently weaned their children. The mean weaning age was 10 months with a standard deviation of 2.1 months. Conduct a hypothesis test to determine if the mean weaning age in the U.S. is less than 10.4 months. Use rejection regions and a 5% level of significance. Assume that the data is normally distributed. (Modified from Illowsky p. 554 #103.)

Answer 1