Page 160 - Probability Demystified

CHAPTER 9 The Normal Distribution 149

The third measure of average is called the mode. The mode is the data value
that occurs most frequently.

EXAMPLE: Find the mode for 22, 27, 30, 42, 16, 30, and 18.

SOLUTION:
Since 30 occurs twice and more frequently than any other value, the mode
is 30.

EXAMPLE: Find the mode for 2, 3, 3, 3, 4, 4, 6, 6, 6, 8, 9, and 10.
SOLUTION:

In this example, 3 and 6 occur most often; hence, 3 and 6 are used as the
mode. In this case, we say that the distribution is bimodal.

EXAMPLE: Find the mode for 18, 24, 16, 15, and 12.
SOLUTION:
Since no value occurs more than any other value, there is no mode.

A distribution can have one mode, more than one mode, or no mode.
Also, the mean, median, and mode for a set of values most often differ
somewhat.

PRACTICE

1. Find the mean, median, and mode for the number of sick days nine
employees used last year. The data are 3, 6, 8, 2, 0, 5, 7, 8, and 5.
2. Find the mean, median, and mode for the number of rooms seven
hotels in a large city have. The data are 332, 256, 300, 275, 216, 314,
and 192.
3. Find the mean, median, and mode for the number of tornadoes that
occurred in a specific state over the last 5 years. The data are
18, 6, 3, 9, and 10.
4. Find the mean, median, and mode for the number of items 9 people
purchased at the express checkout register. The data are
12, 8, 6, 1, 5, 4, 6, 2, and 6.
5. Find the mean, median, and mode for the ages of 10 children who
participated in a field trip to the zoo. The ages are 7, 12, 11, 11, 5,
8, 11, 7, 8, and 6.