In: Statistics and Probability
Use the given data set to complete parts (a) through (c) below. (Use
alphaαequals=0.05.)
x |
10 |
8 |
13 |
9 |
11 |
14 |
6 |
4 |
12 |
7 |
5 |
|
---|---|---|---|---|---|---|---|---|---|---|---|---|
y |
9.13 |
8.13 |
8.75 |
8.77 |
9.27 |
8.11 |
6.14 |
3.09 |
9.14 |
7.26 |
4.73 |
Find the linear correlation coefficient, r, then determine whether there is sufficient evidence to support the claim of a linear correlation between the two variables.
The linear correlation coefficient is
r=______
(Round to three decimal places as needed.)
Solution:
We are given a data set of size n = 11
To find r , we prepare a table.
X | Y | XY | X^2 | Y^2 | |
10 | 9.13 | 91.3 | 100 | 83.3569 | |
8 | 8.13 | 65.04 | 64 | 66.0969 | |
13 | 8.75 | 113.75 | 169 | 76.5625 | |
9 | 8.77 | 78.93 | 81 | 76.9129 | |
11 | 9.27 | 101.97 | 121 | 85.9329 | |
14 | 8.11 | 113.54 | 196 | 65.7721 | |
6 | 6.14 | 36.84 | 36 | 37.6996 | |
4 | 3.09 | 12.36 | 16 | 9.5481 | |
12 | 9.14 | 109.68 | 144 | 83.5396 | |
7 | 7.26 | 50.82 | 49 | 52.7076 | |
5 | 4.73 | 23.65 | 25 | 22.3729 | |
Sum | 99.00 | 82.52 | 797.88 | 1001.00 | 660.50 |
Putting n = 7 , = 797.88 , = 99.00, = 82.52 , = 1001.00 , = 660.50
we get ,
r = 0.817
The linear correlation coefficient is
r = 0.817