Let xi = i for i = 1, 2, . . . , 15, and let the corresponding yi (i = 1, 2, . . . , 15) numbers be (in the order of indeces) 5, 15, 42, 57, 65, 68, 69, 83, 87, 98, 105, 108, 108, 108, 110. Calculate the least squares regression line for these data.
Ans:
x | y | xy | x^2 | |
1 | 5 | 5 | 1 | |
2 | 15 | 30 | 4 | |
3 | 42 | 126 | 9 | |
4 | 57 | 228 | 16 | |
5 | 65 | 325 | 25 | |
6 | 68 | 408 | 36 | |
7 | 69 | 483 | 49 | |
8 | 83 | 664 | 64 | |
9 | 87 | 783 | 81 | |
10 | 98 | 980 | 100 | |
11 | 105 | 1155 | 121 | |
12 | 108 | 1296 | 144 | |
13 | 108 | 1404 | 169 | |
14 | 108 | 1512 | 196 | |
15 | 110 | 1650 | 225 | |
Total | 120 | 1128 | 11049 | 1240 |
slope,b=(15*11049-120*1128)/(15*1240-120^2)=7.2321
y-intercept,a=(1128-7.2321*120)/15=17.343
Regression equation:
y'=7.2321x+17.343
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