In: Statistics and Probability
The data below shows the annual salaries (in millions) and the number of viewers (in millions) of eight television actors and actresses. Answer parts a-c.
Salary (x) |
97 |
12 |
13 |
33 |
11 |
7 |
8 |
2 |
|
Viewers (y) |
16 |
4.9 |
5.3 |
1.6 |
10.4 |
9.1 |
13.4 |
4.7 |
a. Find the value of the linear correlation coefficient r.
b. Find the critical values of r from the table showing the critical values for the Pearson correlation coefficient using alpha=0.05.
c. Is there sufficient evidence to conclude that there is a linear correlation between the two variables?
Solution:
a)
X | Y | XY | X2 | Y2 | |
97 | 16 | 1552 | 9409 | 256 | |
12 | 4.9 | 58.8 | 144 | 24.01 | |
13 | 5.3 | 68.9 | 169 | 28.09 | |
33 | 1.6 | 52.8 | 1089 | 2.56 | |
11 | 10.4 | 114.4 | 121 | 108.16 | |
7 | 9.1 | 63.7 | 49 | 82.81 | |
8 | 13.4 | 107.2 | 64 | 179.56 | |
2 | 4.7 | 9.4 | 4 | 22.09 | |
SUM | 183 | 65.4 | 2027.20 | 11049 | 703.28 |
Putting values we get
r = 0.4938
b)
n = 8
df = n - 2 = 8 - 2 = 6
= 0.05
Using the critical value table for Pearson correlation coefficient, (two tailed )
Critical value are 0.707
c)
r = 0.4938
| r | = | 0.4938 | = 0.4938
r < 0.707
Fail to reject H0
No significance correlation.
No sufficient evidence to conclude that there is a linear correlation between the two variables.