a.
Line of Regression Y on X i.e Y = bo + b1 X
estimating the passer rating based on the percentages of [asses that were touchdowns.
here value of touch downs are dependent variables and the rating will be indendent variable.
X | Y | (Xi - Mean)^2 | (Yi - Mean)^2 | (Xi-Mean)*(Yi-Mean) |
5.6 | 96.8 | 0.09878 | 15.65864 | 1.24372 |
5.7 | 94.7 | 0.17164 | 3.44882 | 0.7694 |
5.1 | 93.2 | 0.03448 | 0.12752 | -0.06631 |
5.4 | 92.9 | 0.01306 | 0.00326 | 0.00653 |
5.2 | 92.3 | 0.00734 | 0.29474 | 0.04653 |
5.1 | 90.1 | 0.03448 | 7.5235 | 0.50936 |
4.9 | 89.9 | 0.14876 | 8.66066 | 1.13508 |
calculation procedure for regression
mean of X = ∑ X / n = 5.2857
mean of Y = ∑ Y / n = 92.8429
∑ (Xi - Mean)^2 = 0.50854
∑ (Yi - Mean)^2 = 35.72
∑ (Xi-Mean)*(Yi-Mean) = 3.64431
b1 = ∑ (Xi-Mean)*(Yi-Mean) / ∑ (Xi - Mean)^2
= 3.64431 / 0.50854
= 7.16622
bo = ∑ Y / n - b1 * ∑ X / n
bo = 92.8429 - 7.16622*5.2857 = 54.96441
value of regression equation is, Y = bo + b1 X
Y'=54.96441+7.16622* X
the regression equation to estimate the rating value based on the given touch down values will be,
Y'=54.96441+7.16622* X
b.
Xi | Yi | Y'=54.96+7.17*X | Y-Y' | (Y-Yi)^2 |
5.6 | 96.8 | 95.095 | 1.705 | 2.907 |
5.7 | 94.7 | 95.812 | -1.112 | 1.237 |
5.1 | 93.2 | 91.512 | 1.688 | 2.849 |
5.4 | 92.9 | 93.662 | -0.762 | 0.581 |
5.2 | 92.3 | 92.229 | 0.071 | 0.005 |
5.1 | 90.1 | 91.512 | -1.412 | 1.994 |
4.9 | 89.9 | 90.079 | -0.179 | 0.032 |
Standard error = Sqrt( ( ∑ Y -Yi )^2/ n-2 )
∑ Y -Yi )^2 = 9.605
Standard Error = 1.386
Standard Error^2 = 1.6745
11. For the National Football League, rating for the all-time leading passers were as shown below....