Question

5. If a four-sided die is rolled 9 times, what is the probability of getting exactly four 2s?

A. ≈ .0009 B. ≈ .0389 C. ≈ .0751 D. ≈ .1168 E. other value

6. If a four-sided die is rolled, find the standard deviation of the number showing. (Hint: First find the variance.)

A. ≈ 1.12 B. ≈ 1.25 C. ≈ 2.50 D. ≈ 7.5 E. other value

7. If a die is rolled 36 times, approximate the probability of getting between four and nine 3s (inclusive).

A. ≈ .6712 B. ≈ .7372 C. ≈ .8104 D. ≈ .8836 E. other value

8. Suppose that test scores on a statistics are normally distributed with a mean of 82% and a standard deviation of 16%. What is the probability that the average test score of a class of 20 students is less than 75%?

A. ≈ .0000 B. ≈ .0250 C. ≈ .9750 D. ≈ 1 E. other value

9. Suppose a simple random sample from a normal population yields the following data: x1 = 20,x2 = 5,x3 =

10,x4 = 13,x5 = 17,x6 = 18. Find a 95% confidence interval for the population mean μ.

A. [11.53,16.13] B. [10.03,17.63] C. [9.32,18.34] D. [7.91,19.75] E. other value

10. How many people would you have to poll to be 95% sure that your margin of error will be less than 3%?

A. 278 B. 757 C. 1,068 D. 1,849 E. other value

Answer 1