mean weight of sixyearold girls in the United States was 493

mean weight of six?year?old girls in the United States was 49.3 pounds. Another NHANES survey, published in 2008, reported that a sample of 194 six?year?old girls weighed between 2003 and 2006 had an average weight of 48.9 pounds. Assume the population standard deviation is sigma = 16.7 pounds. Can you conclude that the mean weight of six?year?old girls in 2006 is different from what it was in 2002? Use the a = 0.05 level of significance and the P?value method with the TI -84 calculator. Part 1 State the appropriate null and alternate hypotheses. H0: Mu 49.3 H1: Mu 49.3 This hypothesis test is a two?tailed test. Part 2 out of 4 Compute the P - value. Round the answer to four decimal places. P - value =

Solution

Part 1

H0: mu =49.3

H1: mu not equal to 49.3

This is two tailed test.

Part2:

test statistics, z = (x-mu)/sigma/sqrt(n) = (48.9-49.3)/(16.7/sqrt(194)) =-0.3361

p-value = 2*P(z<-0.3361) = 2*0.36840 = 0.7368