AP STATISTICS
Period_____ Last 4 of ID________
Quiz on Normal Distribution and Empirical Rule
SHORT ANSWER
1.
2.
A normal distribution follows the Empirical Rule:
a. 68% of the values lie within 1 standard deviation of the mean
b. 95% of the values lie within about 2 standard deviations of the mean
c. 99.7% (or almost all) of the values lie within 3 standard deviations of the mean
a.
b.
c.
The average playing time of compact discs in a large collection is 35 minutes, and the standard deviation is 5 minutes.
a.
Draw the normal curve with proper scaling for
the scenario above.
c.
What percent of the cd’s playing times are below
30 minutes? 0.1587 or About 16%
d.
A playing time of 45 minutes corresponds to what
percentile of cd playing times for this collection?
0.0228 or About 0.2%
Average Playing Time of Compact Discs
b.
The middle 95% of the playing times falls
between what two times? 25 to 45
20
25
30
35
40
45
50
MULTIPLE CHOICE
3.
Suppose that sixteen-ounce bags of chocolate chip cookies are produced with an actual mean weight of 16 ounces and a
standard deviation of 0.1 ounce. The percentage of bags that will contain between 16.0 and 16.1 ounces is:
(a) 10
(b) 16
(c) 34
(d) 68
(e) none of the above
4.
A symmetric, mound-shaped distribution has a mean of 42 and a standard deviation of 7. Which of the following statements
is true?
(a) It is impossible that the distribution contains a data value greater than 70.
(b) There are more data values between 42 and 49 than between 28 and 35.
(c) Approximately 95% of the data lie between 35 and 49.
(d) The interquartile range is approximately 14.
(e) None of these is true.
5.
Which has a larger mean and which has a larger standard deviation?
(a) Larger mean, a; larger standard deviation, a
(b) Larger mean, a; larger standard deviation, b
(c) Larger mean, b; larger standard deviation, a
(d) Larger mean, b; larger standard deviation, b
(e) Larger mean, b; same standard deviation