8.3.1. Collecting and Organizing Data

The following are the grades of 30 students in a monthly math exam:

 25 37 31 39 26 23 27 31 20 33 35 37 23 37 21 33 24 27 36 27 32 26 30 37 25 31 32 21 28 32

Complete the following frequency table with the correct frequencies.

 Grades Total Frequency 30 20– 24– 28– 32– 36–
• A5, 8, 5, 6, 6
• B6, 8, 7, 4, 5
• C3, 7, 5, 8, 7
• D4, 7, 4, 3, 5

Example

The following are the grades of 30 students in a monthly math exam:

 25 37 31 39 26 23 27 31 20 33 35 37 23 37 21 33 24 27 36 27 32 26 30 37 25 31 32 21 28 32

Complete the following frequency table with the correct frequencies.

 Grades Total Frequency 30 20– 24– 28– 32– 36–

Solution

Count the number of grades for each set.

indicates the set of grades that are greater than or equal to 20 and less than 24. There are 5 grades that fall within this range, so the frequency for the set is 5.

indicates the set of grades that are greater than or equal to 24 and less than 28. There are 8 grades that fall within this range, so the frequency for the set is 8.

indicates the set of grades that are greater than or equal to 28 and less than 32. There are 5 grades that fall within this range, so the frequency for the set is 5.

indicates the set of grades that are greater than or equal to 32 and less than 36. There are 6 grades that fall within this range, so the frequency for the set is 6.

indicates the set of grades that are greater than or equal to 36. There are 6 grades that fall within this range, so the frequency for the set is 6.

Using the previous data, the frequency table for the weekly wages can be completed as follows:

 Grades Frequency Total 5 8 5 6 6 30
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correct
0
incorrect
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skipped