Working Hours	TV time per week (minutes)
7	70
26	56
7	73
2	65
1	84
1	82
2	68
4	72
7	72
28	54
30	54
4	75
4	63
1	80
6	64
1	83
6	63
2	70
10	52
8	55
10	55
8	74
18	60
19	68
17	62
15	70
16	64
20	66
21	64
21	62
13	75
14	60
15	76
14	60
12	54
13	60
15	60
14	60
15	75
11	52
13	75
11	53
14	54
12	55
14	54
13	60
11	52
22	60
21	60
4	72
22	56
4	64
34	53
4	62
32	53

A researcher wishes to draw a histogram in presenting graphical summaries of the data on the two main variables concerned - daily TV time in minutes and number of working hours, as stored in 'worktime' worksheet.

1. She decided to use 7 class intervals to construct a histogram for each variable. Explain how the researcher could have decided in using 7 as the number of class intervals to be used.

2. The researcher specified class intervals 0 < X ≤ 5, 5 < X ≤ 10, ..., 30 < X ≤ 35 for the weekly working hours variable. She then specified class intervals 50 < X ≤ 55, 55 < X ≤ 60, ..., 80 < X ≤ 85 for the TV time variable. Explain how the researcher could have decided on the width of each class for these class intervals on each of the two variables.

3.Using Excel, draw and display the histogram for the working hours variable using the class intervals specified in part (b). Comment on the shape of the distribution of the data set as displayed in the histogram.

4. Using Excel, draw and display the histogram for the TV time variable using the class intervals specified in part (b). Comment on the shape of the distribution of the data set as displayed in the histogram.