Question

1. The average number of minutes spent per day using social media by a population of college sophomores is 29.6 minutes. If we take a random sample of size n = 87 from this population and find that the sample standard deviation is 7.3 minutes, we know the sampling distribution of the sample mean in this case would have a standard deviation equal to

A. 4.05 minutes.

B. 1.60 minutes.

C. 0.78 minutes.

D. 7.30 minutes.

E. 3.17minutes.

2. Return to Question 1. What would the mean (or center) of the sampling distribution of the sample mean be equal to?

A. 29.6 minutes

B.11.9 minutes

C. 7.3 minutes

D. 4.1 minutes

E. 3.2 minutes

3. Mrs. Bigelow worries that students at Milpitas High School are not getting enough sleep each night. She decides to survey a random sample of 65 of these students in order to estimate how much sleep all students at Milpitas High School tend to get per weeknight, on average. The 65 students Mrs. Bigelow surveys report getting an average of 7.1 hours of sleep per weeknight, with a standard deviation of 0.9 hours. If Mrs. Bigelow uses this information to construct a 99% confidence interval, what will that interval end up being? Try not to do a lot of intermediate rounding until you get to the end of your calculations, and choose the answer below that is closest to what you obtain.

A. 88 hours to 7.32 hours

B. 6.81 hours to 7.39 hours

C. 7.06 hours to 7.14 hours

D. 4.54 hours to 9.68 hours

E. 4.78 hours to 9.42 hours

4. You have measured the systolic blood pressure of a random sample of 150 employees from a large university. A 95% confidence interval for the mean systolic blood pressure for the employees is computed to be 117 to 137. Which of the following statements is a correct interpretation of this confidence interval? Choose the best answer from those given below.

A. 95% of the sample of employees have a systolic blood pressure between 117 and 137.

B. 95% of the employees from the university have a systolic blood pressure between 117 and 137.

C.We are 95% confident that the confidence interval is from 117 to 137.

D. If the sampling procedure were repeated many times, in the long run, 95% of the resulting confidence intervals would contain the true mean systolic blood pressure of all employees at the university.

E. If the sampling procedure were repeated 100 times, exactly 95 of the sample means would be between 117 and 137.

5. How heavy are the backpacks carried by college students? To estimate the weight of backpacks carried by college students, a researcher weighs the backpacks from a random sample of 58 college students. The average backpack weight ends up being 15.7 pounds, with a standard deviation of 2.4 pounds. If you use this data to construct a 90% confidence interval, what will the margin of error be for this interval? Try not to do a lot of intermediate rounding until you get to the end of your calculations, and choose the answer below that is closest to what you obtain.

A. 1.65 pounds

B. 3.39 pounds

C. 0.52 pounds

D. 0.07 pounds

E. 0.22 pounds

Answer 1