In 2008, the Centers for Disease Control and Prevention reported that 34% of adults in the United States are obese. A county health service planning a new awareness campaign polls a random sample of 750 adults living there. In this sample, 228 people were found to be obese based on their answers to a health questionnaire. Do these responses provide strong evidence that the 34% figure is not accurate for this region? Correct the mistakes you find in a student's attempt to test an appropriate hypothesis.
H0: p̂ = 0.34
HA: p̂ < 0.34
SRS, 750 ≥ 10
228/750 = 0.304; SD(p̂) = √(0.304)(0.696) / 750 = 0.017
z = 0.304 - 0.34 / 0.017 = -2
P = P(z > -2) = 0.977
There is more than a 97% chance that the stated percentage is correct for this region.