A researcher conducts a study to investigate the relationship between cigarette smoking and illness. The number of cigarettes smoked daily and the number of days absent from work in the last year due

A researcher conducts a study to investigate the relationship between cigarette smoking and illness. The number of cigarettes smoked daily and the number of days absent from work in the last year due

A researcher conducts a study to investigate the relationship between cigarette smoking and illness. The number of cigarettes smoked daily and the number of days absent from work in the last year due to illness is determined for 12 individuals employed at the company where the researcher works. The scores are given in the following table.

	Cigarettes	Days
Subject	Smoked	Absent
1	0	1
2	0	3
3	0	8
4	10	10
5	13	4
6	20	14
7	27	5
8	35	6
9	35	12
10	44	16
11	53	10
12	60	16

a. Construct a scatter plot for these data. Does the relationship look linear?

b. Calculate the value of Pearson r.

c. Eliminate the data from subjects 1, 2, 3, 10, 11, and 12. This decreases the range of both variables.

Recalculate r for the remaining subjects. What effect does decreasing the range have on r?

d. If you use the full set of scores, what percentage of the variability in the number of days absent is accounted for by the number of cigarettes smoked daily? Of what use is this value?