5.1. Mean http://www.ck12.org
The mean age of the first group of 3 employees is 43.33 years.
The mean age of the second group of 3 employees is 44.66 years.
The mean age for a sample of a population depends upon what values of the population are included in the sample.
From this example, you can see that the mean of a population and that of a sample from the population are not
necessarily the same.
Example C
The selling prices of the last 10 houses sold in a small town are listed below:
$125,000 $142,000 $129,500 $89, 500 $105, 000
$144,000 $168,300 $96, 000 $182,300 $212, 000
Calculate the mean selling price of the last 10 homes that were sold.
The prices are those of a sample, so the mean of the prices can be calculated as follows:
x=∑
x 1 +x 2 +x 3 +...+xn
n
x=125 , 000 + 142 , 000 + 129 , 500 + 89 , 500 + 105 , 000 +$144, 000 + 168 , 300 + 96 , 000 + 182 , 300 + 212 , 000
10
x=$1, 393 , 600
10
x=$139, 360The mean selling price of the last 10 homes that were sold was $139,360.
The mean value is one of the 3 m’s and is a measure of central tendency. It is a summary statistic that gives you a
description of the entire data set and is especially useful with large data sets, where you might not have the time to
examine every single value. You can also use the mean to calculate further descriptive statistics, such as the variance
and standard deviation. These topics will be explored in a future concept. The mean assists you in understanding
and making sense of your data, since it uses all of the values in the data set in its calculation.
Guided Practice
During his final season with the Cadillac Selects, Joe Sure Shot played 14 regular season basketball games and had
an average of 24.5 points per game. In the first 2 playoff games, Joe scored 18 and 26 points, respectively. Determine
his new average for the season.
Answer:
Step 1:Multiply the given average by 14 to determine the total number of points he had scored before the playoff
games.
24. 5 × 14 = 343
Step 2:Add the points from the 2 playoff games to this total.