Suppose that a random sample of size 64 is to be selected from a

population with a mean 40 and standard deviation 5.

1. What is the population mean?

A. 5

B. 25

C. 30

D. 40

2. What is the standard deviation of the sampling distribution?

A. 0.625

B. 2.10

C. 21.5

D. 22.5

3. What is the approximate probability that will be within 0.5 of the

population mean ?

A. 31.5%

B. 32.80%

C. 57.62%

D. 75.57%

4. What is the approximate probability that will differ from by more than 0.7?

A. 26.27%

B. 34.23%

C. 39.3%

D. 40.7%

The GPAs of all students enrolled at a large university have an

approximately normal distribution with a mean of 3.05 and a standard deviation

of 0.29. Find the probability that the mean GPA of a random sample of 20 students

selected from this university is:

5. less than 298?

A. 12.58%

B. 14.01%

C. 15.62%

D. 85.23%

6. greater than 3.01?

A. 19.32%

B. 22.41%

C. 55.56%

D. 73.24%

7. between 2.90 and 3.07?

A. 62.17%

B. 61.13%

C. 42.34%

D. 1.04%

8. The standard error of the mean is smaller when N = 20 than when N = 10.

A. true

B. false

C. sometimes

D. maybe

9. A normal distribution is standardized by the formula

A. nπ

B. nπ(1-π)

C. (x - µ)/ σ

D. (x - µ)/ n

10. The mean of the standard normal distribution is

A. 0 B. 1 C. 100 D. 1000

Assume that woman’s heights are normally distributed with a mean given

by = 62.3 inches and a standard deviation σ = 1.8 inches.

11. If a woman is randomly selected, find the probability that her height is between

61.7 inches and 62.7 inches?

A. 20.75%

B. 72%

C. 21.64%

D. 86.65%

12. If a sample of 16 women is selected, what is the probability that the mean of

the sample will be larger than 63.2 inches?

A. 19.32%

B. 15.56%

C. 4.75%

D. 2.28%

13. If a sample of 16 women is selected, what is the probability that the mean of

the sample will be less than 63.2 inches?

A. 97.72%

B. 41.56%

C. 28.74%

D. 16.67%

14. Which is NOT true about the standard error?

A. The standard error is also the sampling error.

B. The standard error is the approximate standard deviation of a statistical

sample population.

C. The more data points involved in the calculations of the mean, the

smaller the standard error tends to be.

D. The standard error can include the variation between the calculated

mean of the population and one which is considered known, or accepted

as accurate.

15. The number of total carbohydrates in an order of camote fries in a native

restaurant is approximately normally distributed with a mean of 240 and a

standard deviation of 20. What is the probability that a randomly selected

order has at least 265 total carbohydrates?

A. 54.13%

B. 34.67%

C. 21.56%

D. 10.56%

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