Page 184 - Probability Demystified

CHAPTER 9 The Normal Distribution 173

7. The area under the standard normal distribution is

a. 1 or 100%
b. 0.5 or 50%
c. Unknown
d. Infinite
8. For the standard normal distribution,
a. The mean ¼ 1 and the standard deviation ¼ 0.
b. The mean ¼ 1 and the standard deviation ¼ 2.
c. The mean ¼ 0 and the standard deviation ¼ 1.
d. The mean and standard deviation can both vary.

9. What percent of the area under the standard normal distribution lies
within two standard deviations of the mean?

a. 68%
b. 95%
c. 100%
d. Unknown

10. When the value of a variable is transformed into a standard normal
variable, the new value is called a(n)

a. x value
b. y value
c. 0 value
d. z value
Use Table 9-1 to answer questions 11 through 15.
11. The area under the standard normal distribution to the right of
z ¼ 0.9 is
a. 90.1%
b. 18.4%
c. 81.6%
d. 10.2 %

12. The area under the standard normal distribution to the left of
z ¼ 1.2 is

a. 88.5%
b. 62.3%
c. 48.7%
d. 11.5%