Percents

Frequency tables are a useful method for displaying information because many calculations can be made from the information. Percent is one calculation that can be derived from a frequency table.

Unique Numbers in Data Set
Frequency
(Number of Times Data Value Appears)
1
2
3
2
4
3
5
2
7
1
8
1
12
1
15
1
17
1

If we want to know what percentage of the data values are the number 3, we look at the chart and find that there are a total of 14 values (n = 14) with the number 3 appearing two times. We know that to find percentage, we use the following equation:

( frequency of x / n ) * 100 = percentage of x

In our example, we divide 2 by 14 and multiply the answer by 100. This gives us 14.29%. Percentages are another efficient method to display data because they are easy to understand and are fast to read.

Quick Quiz: What percentage of data values are 12 degrees C or below?

8
9
11
12
13
14
15
7
9
11
13
14
15
16
8
9
14
18
20
20
18
9
9
16
19
22
24
24
10
11
18
20
22
25
25
12
14
19
20
22
24
25
14
18
19
21
22
23
24
18
19
20
21
22
23
23


400%
25%
0.0025%
0.25%

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