In: Statistics and Probability
Annual high temperatures in a certain location have been tracked
for a sample of 13 years. Let X represent the year and Y the high
temperature (in C∘).
Years | Temperature in C∘C∘ |
---|---|
2 | 9.5 |
3 | 9.35 |
4 | 11.2 |
5 | 11.35 |
6 | 10.6 |
7 | 12.95 |
8 | 13.7 |
9 | 13.45 |
10 | 12.2 |
11 | 12.65 |
12 | 15.9 |
13 | 15.55 |
14 | 14.3 |
1) Calculate the correlation coefficient. (Round to three
decimal places.)
r=
Let's test the significance of the correlation coefficient at α=0.05 significance level.
H0: There is not a significant relationship between the year and
high temperature, i.e., ρ=0.
Ha: There is a significant relationship between the year and high
temperature, i.e., ρ≠0
Following table shows the calculations:
X | Y | X^2 | Y^2 | XY | |
2 | 9.5 | 4 | 90.25 | 19 | |
3 | 9.35 | 9 | 87.4225 | 28.05 | |
4 | 11.2 | 16 | 125.44 | 44.8 | |
5 | 11.35 | 25 | 128.8225 | 56.75 | |
6 | 10.6 | 36 | 112.36 | 63.6 | |
7 | 12.95 | 49 | 167.7025 | 90.65 | |
8 | 13.7 | 64 | 187.69 | 109.6 | |
9 | 13.45 | 81 | 180.9025 | 121.05 | |
10 | 12.2 | 100 | 148.84 | 122 | |
11 | 12.65 | 121 | 160.0225 | 139.15 | |
12 | 15.9 | 144 | 252.81 | 190.8 | |
13 | 15.55 | 169 | 241.8025 | 202.15 | |
14 | 14.3 | 196 | 204.49 | 200.2 | |
Total | 104 | 162.7 | 1014 | 2088.555 | 1387.8 |
--------------------------------------------
Conclusion: There is a significant relationship between the year and high temperature, i.e., ρ≠0