Question

The CDC publishes charts on Body Mass Index (BMI) for boys and girls of different ages. Based on the chart for girls, the mean BMI for 6-year-old girls is listed as 15.8 kg/m2. The data from which the CDC charts were developed is old and there is concern that the mean BMI for 6 year olds girls has increased.

The BMI’s from a current random sample of 50 6-year-old girls is attached in a list on the next page. Use this data of current six-year girls to test the claim that the mean BMI for current girls is greater than 15.8 (thus, testing that the mean BMI for six-year-old girls has increased since the chart was made).

1. State the claim, null hypothesis, and alternate hypothesis in symbols.

Claim:

H0 : ?

H1: ?

2. Copy and paste the sample of 50 BMI’s into stat crunch. Calculate the mean and standard deviation for the sample.

Mean = ?

Standard deviation = ?

3. Use stat crunch to run a hypothesis test for mean. Go to stat > t-stats > one-sample > with data. (you can also choose “with summary” and enter your sample mean and sample standard deviation from part 2)

**Enter your information for your null hypothesis and alternative hypothesis (make sure to select the appropriate inequality sign for your alternate hypothesis).

Record your p-value: ____________

4. Based on your p-value, do you reject your null hypothesis or fail to reject your null hypothesis? Use a 0.05 significance level.

5. Based on your answer #3 and #4, does the sample data provide sufficient evidence that the mean BMI for 6-year-old girls has increased? Explain.

Math 1740 92 Week 7 – Hypothesis Testing Assignment

24.5 16.3 15.7 20.6 15.3 14.5 14.7 15.7 14.4 13.2 16.3 15.9 16.3 13.5 15.5 14.3 13.7 14.3 13.7 16 14.2 17.3 19.5 22.8 16.4 15.4 18.2 13.9 17.6 15.5 17.8 15.2 18.9 17.7 13.7 21 18.4 14.7 16.9 13.8 14.9 14.1 17.6 13.6 22.6 15.1 18.1 16.8 14.2 13.3

Answer 1