Question

The average cholesterol level in the general US population is 189 mg/dL. A researcher wants to see if the average cholesterol for men in the US is different from 189 mg/dL. She takes a sample of 81 American males and finds a sample mean of 194 mg/dL and a sample standard deviation of 10.4

1.) What is the 90% confidence interval?

2.) What is the correct interpretation of the confidence interval from question 11?

3.) Are the assumptions met? Explain.

4.) Conduct a hypothesis test at the 0.10 significance level to test the researcher’s question. What are the hypotheses?

5.) What is the significance level? A. 0.01 B. 0.04 C. 0.05 D. 0.10

6.) What is the value of the test statistic?

7.) What is the p-value?

8.) What is the correct decision? A. Reject the Null Hypothesis B. Fail to Reject the Null Hypothesis C. Accept the Null Hypothesis D. Accept the Alternative Hypothesis

9.) . What is the appropriate conclusion/interpretation?

10.) Are the assumptions met? Explain.

Answer 1

(2) We are 90% confident that the true average cholesterol level for men in the US lies between 192.08 mg/dL and 195.92 mg/dL. Since this interval does not contain the value of 189 mg/dL, we can say that the average cholesterol for men in the US is significantly different from 189 mg/dL.

(3) Yes, the assumptions are met, since the sample size of 81 is significantly greater than 30 and the sample that has been drawn is random. Also, the variable "cholesterol level of men in the US" is a continuous variable and it does not contain any outliers.

(9) We conclude that there is enough evidence to suggest that the average cholesterol for men in the US is significantly different from 189 mg/dL.

(10) Yes, the assumptions are met, since the sample size of 81 is significantly greater than 30 and the sample that has been drawn is random. Also, the variable "cholesterol level of men in the US" is a continuous variable and it does not contain any outliers.