3. Mean : The balance point of a set of data.
Mean = sum of all data points divided by the number of data points
Let’s review the measure known as the mean. The mean is the balance point of a set of data. The mean is calculated by the sum of all data points in the data set by the number of data points.

4. A common mistake is not carefully counting the number of items that you are using to calculate the mean. This is particularly important when you have a long list of items.

5. Measures of Central Tendency
Mean, Median, & Mode
The measures of central tendency, also known as mean, median, and mode, are used to describe a “typical” item in a set of data. You have already learned how to calculate them. In this lesson we are going to use them as a tool to compare different sets of data to each other. Each measure is more appropriate in certain cases. In this lesson, I will focus on the mean. The mean is used when there are no extreme values. All of the values are used to calculate the mean.

6. Cougars x l l l l l l l l l l l x l l l l l l l l l l l x x
l l l l l l l l l l l
Cougars
Here we have a line plot representing the number of wins each team has had for the past 6 seasons. We have to take each number that each x represents and use them to calculate the mean. Just looking at the graph, it is hard to guess a mean because the data sets look so differently on the line plot.

7. Flamingos Mean: 31+31+38+42+47+50 6 = 39.8
Cougars Mean =40.2
We add up the total wins for each of the last six seasons for each time and divide by 6 because we have six numbers. Although it appears that the cougars had seasons with a higher number of wins, it turns out that the means for both teams less than one point away from each other. The Cougars, however have a slight edge over the Flamingos.

8. AFC Mean: 80+67+114+76+94+78+82 6 =84.2 NFL Team Penalties NFC AFC 8659 67
137
114 68 76
113 94 77 78
104 82
AFC Mean: =84.2
Let look at another example. Here we have a listing of penalties by teams for the top teams in the NFC and AFC conferences of the NFL. We want to take the mean of each conference to see if we can compare the number of team penalties for each conference.
We add up the total penalties for each of the conference teams and divide by 7 because we have data from 7 teams in each conference.
The NFC has a higher mean or average number of penalties, so we can infer that the top NFC teams are penalized more during their games.

10. USA
Year
Medals
1992
108
1996
101
2000 92
2004
103
2008
110
RUSSIA
Year
Medals
1992
112
1996 63
2000 88
2004 92
2008
100

13. Week 1 Week 2 x l l l l l l l l l l l l l
Week 1
Week 2 x

14. Minutes of Exercise
Week 1
Week 2 45 30 40 55 35 60 90 75