1. Learn to find the range, mean, median, and mode of a data set.

2. The range is the difference between the least and greatest numbers in the set.
Find the range for the data set.
Depths of Puddles (in.) 5 8 3 4 2 1
Start by writing the data in numerical order.
1, 2, 3, 4, 5, 5, 8
range: 8 – 1 = 7
Subtract least value from greatest value.
The range is 7 inches

3. The mean is the sum of all the items, divided by the number of items in the set. (The mean is sometimes called the average.)
Find the mean for the data set. A.
Depths of Puddles (in.) 5 8 3 4 2 1
Start by writing the data in numerical order.
1, 2, 3, 4, 5, 5, 8
mean: = 28
28 ÷ 7 = 4
Add all values.
Divide the sum by the number of items.
The mean is 4 inches

4. The median is the middle value when the data are in numerical order, or the mean of the two middle values if there are an even number of items.
Find the median for the data set.
Depths of Puddles (in.) 5 8 3 4 2 1
Start by writing the data in numerical order.
1, 2, 3, 4, 5, 5, 8
median: 4
There are an odd number of items, find the middle value.
The median is 4 inches

5. The mode is the value or values that occur most often
The mode is the value or values that occur most often. There be more than one mode for a data set. When all values occur an equal number of times, the data set has no mode.
Find the mode for the data set.
Depths of Puddles (in.) 5 8 3 4 2 1
Start by writing the data in numerical order.
1, 2, 3, 4, 5, 5, 8
mode: 5
5 occurs most often.
The mode is 5 inches

6. Number of Points Scored
Find the range, mean, median, and mode of the data set below.
Number of Points Scored 96 75 84 7
Write the data in numerical order.
7, 75, 84, 96
range: 96 – 7 = 89
mean: 4
= 65.5
median: 7, 75, 84, 96
There are an even number of items, so find the mean of the two middle values. 2
= 79.5
mode: none
The range is 89 points; the mean is 65.5 points; the median is 79.5 points; and there is no mode.

7. Find the range, mean, median, and mode of the data set below.
Rainfall per month (in.) 1 2 10 5 6 9
Start by writing the data in numerical order.
1, 2, 2, 5, 6, 9, 10
range: 10 – 1 = 9
Subtract least value from greatest value.
mean: = 35
35 ÷ 7 = 5
Add all values.
Divide the sum by the number of items.
median: 5
There are an odd number of items, find the middle value.
mode: 2
2 occurs most often.
The range is 9 in.; the mean is 5 in.; the median is 5 in.; and the mode is 2 in.

8. Number of Points Scored
Find the range, mean, median, and mode of the data set below.
Number of Points Scored 53 26 47 12
Write the data in numerical order.
12, 26, 47, 53
range: 53 – 12 = 41
mean: 4
= 34.5
median: 12, 26, 47, 54
There are an even number of items, so find the mean of the two middle values. 2
= 36.5
mode: none
The range is 41 points; the mean is 34.5 points; the median is 36.5 points; and there is no mode.

9. Range, Mean, Median, and Mode
Some descriptions of a set of data are called the range, mean, median, and mode.
The range is the difference between the least and greatest values in the set. (Subtract the smaller number from the larger number)
The mean is the sum of all the items, divided by the number of items in the set. (The mean is sometimes called the average.) Add all of the numbers together and divide by the number of numbers you added together)
The median is the middle value when the data are in numerical order, or the mean of the two middle values if there are an even number of items.
The mode is the value or values that occur most often. There may be more than one mode for a data set. When all values occur an equal number of times, the data set has no mode.