In: Statistics and Probability
Age | Weight (pounds) |
56 | 156 |
35 | 110 |
22 | 80 |
57 | 91 |
40 | 90 |
22 | 150 |
48 | 165 |
48 | 99 |
25 | 189 |
40 | 178 |
25 | 123 |
25 | 190 |
59 | 255 |
49 | 112 |
33 | 155 |
56 | 134 |
20 | 117 |
31 | 91 |
27 | 100 |
23 | 80 |
45 | 190 |
29 | 255 |
31 | 112 |
59 | 200 |
39 | 134 |
35 | 110 |
44 | 99 |
27 | 110 |
24 | 180 |
27 | 150 |
a) What is the expected weight of an individual that is 27 years old?
b) How much variability in weight is accounted for by an individual’s age?
c) How much variability in weight is accounted for by factors other than age?
d) Assume alpha is 0.05 Is an individual’s weight a significant predictor of an individual’s age? Provide the specific statistical evidence from your Excel output to support your answer.
(a) The model is:
Weight = 113.9148 + 0.7153*Age
The expected weight of an individual that is 27 years old is 133.228.
(b) 0.035
(c) 0.965
(d) The hypothesis being tested is:
H0: β1 = 0
H1: β1 ≠ 0
The p-value is 0.3189.
Since the p-value (0.3189) is greater than the significance level (0.05), we fail to reject the null hypothesis.
Therefore, we cannot conclude that an individual’s weight is a significant predictor of an individual’s age.
r² | 0.035 | |||||
r | 0.188 | |||||
Std. Error | 47.834 | |||||
n | 30 | |||||
k | 1 | |||||
Dep. Var. | Weight (pounds) | |||||
ANOVA table | ||||||
Source | SS | df | MS | F | p-value | |
Regression | 2,355.8722 | 1 | 2,355.8722 | 1.03 | .3189 | |
Residual | 64,066.2945 | 28 | 2,288.0819 | |||
Total | 66,422.1667 | 29 | ||||
Regression output | confidence interval | |||||
variables | coefficients | std. error | t (df=28) | p-value | 95% lower | 95% upper |
Intercept | 113.9148 | |||||
Age | 0.7153 | 0.7049 | 1.015 | .3189 | -0.7287 | 2.1593 |
Predicted values for: Weight (pounds) | ||||||
95% Confidence Interval | 95% Prediction Interval | |||||
Age | Predicted | lower | upper | lower | upper | Leverage |
27 | 133.228 | 110.508 | 155.949 | 32.645 | 233.811 | 0.054 |
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