Question

The body mass index (BMI) of a person is the person’s weight divided by the square of his or her height. It is an indirect measure of the person’s body fat and an indicator of obesity. Results from surveys conducted by the Centers for Disease Control and Prevention (CDC) showed that the estimated mean BMI for US adults increased from 25.0 in the 1960–1962 period to 28.1 in the 1999–2002 period. [Source: Ogden, C., et al. (2004). Mean body weight, height, and body mass index, United States 1960–2002. Advance Data from Vital and Health Statistics, No. 347.]

Suppose you are a health researcher. You conduct a hypothesis test to determine whether the mean BMI of US adults in the current year is lower than the mean BMI of US adults in 2000. Assume that the mean BMI of US adults in 2000 was 28.1 (the population mean). You obtain a sample of BMI measurements of 1,034 US adults, which yields a sample mean of M = 28.9.

Let μ denote the mean BMI of US adults in the current year. Formulate your null and alternative hypotheses by selecting the appropriate values in the blue dropdown menus that follow.

H₀:
H₁:

The test you conduct is   test.

Answer 1

ACCORDING TO QUESTION , THE NULL AND ALTERNATIVE HYPOTHESES ARE :

H₀ : BMI of US adults in the current year is equal to the mean BMI of US adults in 2000. , = 28.1

H₁ : BMI of US adults in the current year is lower than the mean BMI of US adults in 2000. , < 28.1 .

And , the test to be conducted is z test for single sample . where n = 1034 > 30 .

so , Z = { (xbar - )/ (/sqrt(n) ) } .

I HOPE I WAS HELPFUL AND HAVE CLEARED YOUR DOUBTS.

THANKYOU