In: Statistics and Probability
Consider the data.
xi |
1 | 2 | 3 | 4 | 5 |
---|---|---|---|---|---|
yi |
4 | 7 | 5 | 11 | 15 |
The estimated regression equation for these data is ŷ = 0.60 + 2.60x.
(a)Compute SSE, SST, and SSR using equations SSE = Σ(yi − ŷi)2, SST = Σ(yi − y)2, and SSR = Σ(ŷi − y)2.
SSE=SST=SSR=
(b) Compute the coefficient of determination r2.
r2 =
Comment on the goodness of fit. (For purposes of this exercise, consider a proportion large if it is at least 0.55.)
A) The least squares line did not provide a good fit as a small proportion of the variability in y has been explained by the least squares line.
B) The least squares line provided a good fit as a small proportion of the variability in y has been explained by the least squares line.
C) The least squares line provided a good fit as a large proportion of the variability in y has been explained by the least squares line.
D) The least squares line did not provide a good fit as a large proportion of the variability in y has been explained by the least squares line.
(c)Compute the sample correlation coefficient. (Round your answer to three decimal places.)
The given data is:
x | y |
1 | 4 |
2 | 7 |
3 | 5 |
4 | 11 |
5 | 15 |
Using Excel<data<megastat<correlation/regression<regression
Regression Analysis | ||||||
r² | 0.813 | |||||
r | 0.901 | |||||
Std. Error | 2.280 | |||||
n | 5 | |||||
k | 1 | |||||
Dep. Var. | y | |||||
ANOVA table | ||||||
Source | SS | df | MS | F | p-value | |
Regression | 67.6000 | 1 | 67.6000 | 13.00 | .0366 | |
Residual | 15.6000 | 3 | 5.2000 | |||
Total | 83.2000 | 4 | ||||
Regression output | confidence interval | |||||
variables | coefficients | std. error | t (df=3) | p-value | 95% lower | 95% upper |
Intercept | 0.6000 | 2.39 | 0.25 | 0.82 | -7.01 | 8.21 |
x | 2.6000 | 0.7211 | 3.606 | .0366 | 0.3051 | 4.8949 |
a)
SSE= 15.6
SST= 83.2
SSR= 67.6
b)
r^2=0.813
The least squares line provided a good fit as a large proportion of the variability in y has been explained by the least squares line
c) r= 0.901
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