dolution

Low Birth Weight According to the U.S. Census Bureau, 7.1% of all babies born are of low birth weight . An obstetrician wanted to know whether mothers between the ages of 35 and 39 years give birth to a higher percentage of low-birth-weight babies. She randomly selected 240 births for which the mother was 35 to 39 years old and found 22 low-birth-weight babies.

(a) If the proportion of low-birth-weight babies for mothers in this age group is 0.071, compute the expected number of low-birth-weight births to 35- to 39-year-old mothers. What is the expected number of births to mothers 35 to 39 years old that are not low birth weight?

(b) Answer the obstetrician’s question at the  level of significance using the chi-square goodness-of-fit test.

(c) Answer the question by using the approach presented in Section 10.2.