In: Statistics and Probability
Here is a bivariate data set.
x | y |
---|---|
77.2 | 35 |
84 | 32.8 |
68.1 | 34.9 |
81 | 27.8 |
91.3 | 25.6 |
79.9 | 30.1 |
80.9 | 30 |
90.3 | 27.1 |
69.3 | 29.3 |
73.3 | 34.3 |
86 | 31 |
Find the correlation coefficient and report it accurate to three
decimal places.
r =
Solution:
X | Y | XY | X^2 | Y^2 |
77.2 | 35 | 2702 | 5959.84 | 1225 |
84 | 32.8 | 2755.2 | 7056 | 1075.84 |
68.1 | 34.9 | 2376.69 | 4637.61 | 1218.01 |
81 | 27.8 | 2251.8 | 6561 | 772.84 |
91.3 | 25.6 | 2337.28 | 8335.69 | 655.36 |
79.9 | 30.1 | 2404.99 | 6384.01 | 906.01 |
80.9 | 30 | 2427 | 6544.81 | 900 |
90.3 | 27.1 | 2447.13 | 8154.09 | 734.41 |
69.3 | 29.3 | 2030.49 | 4802.49 | 858.49 |
73.3 | 34.3 | 2514.19 | 5372.89 | 1176.49 |
86 | 31 | 2666 | 7396 | 961 |
n | 11 |
sum(XY) | 26912.77 |
sum(X) | 881.30 |
sum(Y) | 337.90 |
sum(X^2) | 71204.43 |
sum(Y^2) | 10483.45 |
Numerator | -1750.80 |
Denominator | 2736.31 |
r | -0.6398 |
r square | 0.4094 |
Xbar(mean) | 80.1182 |
Ybar(mean) | 30.7182 |
SD(X) | 6.9973 |
SD(Y) | 3.5274 |
b | -0.2669 |
a | 52.1041 |
r = -0.640