Question

The sample data below lists the number of minutes Internet subscribers spent on the Internet during their most recent session at the time of the survey.

50 40 41 17 11 7 22 44 28 21 19 23 37 51 54 42 86 41 78 56 72 56 17 7 69 30 80 56 29 33 46 31 39 20 18 29 34 59 73 77 36 39 30 62 54 67 39 31 53 44

A. Construct an expanded frequency distribution table for the example by giving the 7 classes, their frequencies, their midpoints, their relative frequencies, and the cumulative frequencies for each class.

B. Construct a frequency histogram for the Internet usage frequency distribution using class midpoints. Show appropriate axes and scale labels.

C. Now construct a relative frequency histogram for the Internet usage table, using class boundary labels.

D. Now construct a stemplot (stem and leaf plot) for this same data, using one row per stem and showing a Key that explains a typical score. Rearrange the leaves in smallest to largest order, so that the data is sorted in your final stemplot.

Answer 1

(a)

Minimum Value = 7

Maximum value = 86

Number of classes: 7

So, class width

class width = ( maximum - minimum) / 7 = (86-7) / 7 = 12 (approx)

Midpoint =(lower limit + upper limit) / 2

Relative frequency = Frequency / n

Here n shows the number of data values.

Following is the completed table:

b:

c:

d: