Question

shopping times (in minutes)
22 30 38 27 28 34
30 19 32 15 24 31
33 26 17 20 21 23
(a) complete the grouped frequency distribution for the data. (note that the class width is 6.)
shopping times (in minutes) frequency
15 to 20
21 to 26
27 to 32
33 to 38
(b) construct a histogram for the data.
frequency
↑
7
6
5
4
3
2
1
0
15 to 20 21 to 26 27 to 32 33 to 38
shopping times (in minutes)

Explanation:

Step1: Count data in 15 - 20

The numbers in the range 15 to 20 are 15, 19, 17, 20. So the frequency is 4.

Step2: Count data in 21 - 26

The numbers in the range 21 to 26 are 24, 26, 21, 23. So the frequency is 4.

Step3: Count data in 27 - 32

The numbers in the range 27 to 32 are 27, 28, 30, 32, 30, 31. So the frequency is 6.

Step4: Count data in 33 - 38

The numbers in the range 33 to 38 are 38, 33. So the frequency is 2.

Answer:

Shopping times (in minutes)	Frequency
21 to 26	4
27 to 32	6
33 to 38	2

To construct the histogram:

• For the interval 15 - 20, draw a bar with height 4.
• For the interval 21 - 26, draw a bar with height 4.
• For the interval 27 - 32, draw a bar with height 6.
• For the interval 33 - 38, draw a bar with height 2.