Chapter 1, Problem R1.5RE

(a)

To determine

To find: the distributions of Facebook use for every of the three age groups and construct the bar graph to compare the distributions.

Explanation of Solution

Calculation:

The study is including 219 students.

Let us first find the row/ column totals, which is the sum of all counts in the row/column:

	Younger	Middle	Older	Total
Yes	78	49	21	148
No	4	21	46	71
total	82	70	67	219

To find the distribution of Facebook use from every age category, divide the counts by the column total.

	Younger	Middle	Older
Yes	95.12%	70%	31.34%
No	4.88%	30%	68.66%

Graph:

  

The width of each bar has to be the same and the height has to be equal to the percent.

(b)

To determine

To Explain: the graph in part (a) reveals about the association between Facebook use and age.

Explanation of Solution

Given:

From part (a)

  

It is observed that as the age increases, the Facebook use looks to decrease, the reason is that the area of blue section of the bars decreases as the age increases.

Moreover, the majority of the younger and middle students use Facebook, because the associating bars have a large blue area compared to the green area. However, the majority of the students do not use Facebook, because the associating bars have a larger green area compared to the blue area.