Name:    SOL A.9 Z SCORES MINI QUIZ

Multiple Choice
Identify the choice that best completes the statement or answers the question.

1.

A speed reading course claims that it can boost reading speeds to 1050 words per minute.
In a random sample of 49 people who took the course, the average was 1020 words per minute, with a standard deviation of 90 words per minute. What is the z-value rounded to the nearest hundredth?
 a. The z-value is –2.33. b. The z-value is –16.33. c. The z-value is –1.96. d. The z-value is 1.96.

2.

An automobile insurance company claims that its rates for teenage drivers average \$410 less per year than the same coverage from another company.
In a random sample of 35 customers, the average savings was \$390 per year, with a standard deviation of \$55 per year. What is the z-value rounded to the nearest hundredth?
 a. The z-value is 1.87 b. The z-value is -1.87 c. The z-value is –2.15. d. The z-value is 2.15

3.

Suppose that a certain website claims that it averages 4.7 hours of downtime per month. (Downtime is time that the site is not available.)
In a random sample of 17 months, the average downtime was 4.9 hours per month, with a standard deviation of 0.5 hours per month. What is the z-value rounded to the nearest hundredth?
 a. The z-value is 1.65. b. The z-value is -2.21 c. The z-value is -1.65. d. The z-value is 2.21