Practice Examples
You will need paper, pencil and calculator. 

1.

The weekly salaries of six employees at McDonalds are
$140, $220, $90, $180, $140, $200. For these six salaries, find: (a) the mean (b) the median (c) the mode
ANSWER

2. 
Andy has grades of 84, 65, and 76 on three math tests.
What grade must he obtain on the next test to have an average of exactly 80 for the four tests?
ANSWER

3. 
Test scores for a class of 20 students are as follows:
93, 84, 97, 98, 100, 78, 86, 100, 85, 92, 72, 55,
91, 90, 75, 94, 83, 60, 81, 95
Test
Scores 
Frequency 
91100 

8190 

7180 

6170 

5160 


a) Copy and complete the table shown
at the left.
b) Find the modal interval.
The "modal interval" is the interval
containing the greatest frequency. It is not the mode.
c) Find the interval that contains the
median. 
ANSWER

4. 
a.) A storeowner kept a tally
of the sizes of suits purchased in her store. Which measure of central tendency should the storeowner use to
describe the average size suit sold?
b.) A tally was made of the
number of times each color of crayon was used by a kindergarten class.
Which measure of central tendency should the teacher use to determine which
color is the favorite color of her class?
c.) The science test grades are posted. The
class did very well. All students taking the test scored over 75.
Unfortunately, 4 students were absent for the test and the computer listed
their scores as 0 until the test is taken. Assuming that no score
repeated more times than the 0's, what measure of central tendency would
most likely give the the best representation of this data?
ANSWERS

5. 
In January of 2006, your
family moved to a tropical climate. For the year that followed, you
recorded the number of rainy days that occurred each month. Your data
contained 14, 14, 10, 12, 11, 13, 11, 11, 14, 10, 13, 8.
a. Find the mean, mode, median and range for your data set of rainy
days.
b. If the number of rainy days doubles each month in the year 2007,
what will be
the mean, mode, median and range for the 2007 data?
c. If, instead, there are three more rainy days per month in the year
2007, what will
be the mean, mode, median and range for the 2007 data?
ANSWERS

6. 

The values of 11 houses on Washington Street are shown in the table.
a. Find the mean value of these houses in
dollars.
b. Find the median value of these houses in
dollars.

c. State which measure of central tendency, the mean or
the median, best represents the values of these 11 houses. Justify
your answer.
ANSWERS 
