Mean  Measures of Central Tendency
Mean
In this section, we practice calculating the mean of a data set. You may think your math teacher is mean if she says you are average! The word mean is often used simultaneously with the word average. The mean is calculated by dividing the sum of a set of values by the number of values in the set. In this
section, we use the mean of a data set to make predictions about the data. In this section, we are first given sets of data and asked to calculate the mean of each set. Then, we are given word problems and asked to make predictions about given sets of data, using what we know about the mean. For example, we are asked to determine how a given set of data would need to change in order to alter the mean by a specified amount.
Basic concepts:
 Divisibility rules
 Introduction to Exponents
 Median and mode
Related concepts:
 Influencing factors in data collection
 Probability
Lessons

1.
Calculate the mean of each set of data. Round your answer to the nearest tenth.

2.
A survey collected information about the total amount of time teens spent on computers each week. Only data from four cities is listed below.
Cities
Computer time (hours per week)
A
15.3
B
17.5
C
12.4
D
13.9

3.
Harry was given the following marks on his English essays:
69%, 71%, 85%, 80%, 93%, 99%