Question

Child Health and Development Studies (CHDS) has been collecting data about expectant mothers in Oakland, CA since 1959. One of the measurements taken by CHDS is the weight increase (in pounds) for expectant mothers in the second trimester. In a fictitious study, suppose that CHDS finds the average weight increase in the second trimester is 14 pounds. Suppose also that, in 2015, a random sample of 35 expectant mothers have mean weight increase of 16.1 pounds in the second trimester, with a standard deviation of 5.9 pounds. A hypothesis test is done to see if there is evidence that weight increase in the second trimester is greater than 14 pounds. Find the p -value for the hypothesis test.

Answer 1

Since the population standard deviation is unknown we use t test for one sample

The test statistic is

The p value for the value 2.105 at 34 degrees of freedom is 0.0214<0.05 ( Statistically significant)which indicates to reject the null hypothesis and accept the alternate claim at 5% level of significance that the mean weight increase is greater than 14.