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GI 72% D ooooo Sprint LTE 9:39 AM bb.wpunji.edu Part (a) (2 points Using the \"S

ID: 3218245 • Letter: G

Question

GI 72% D ooooo Sprint LTE 9:39 AM bb.wpunji.edu Part (a) (2 points Using the "School Bus Data.xlsx" file, run a regression with "Maintenance cost per month" as the dependent O)variable and "Age" as the independent (X)variable. You must submit your actual Excel file with the output as part of the assignment. Part (b) (2 points) Explain why it makes sense to claim that there is causation going from "Age" to "Maintenance cost per month, i e, what is the "story" we can tell that explains why changes in the age of buses plausibly have an impact on the buses' maintenance cost. Part (c) (2 points) Interpret the estimated value of the coefficient on "Age," i.e., explain what the number means in this regression. Part (d) (2 points) How high are the predicted maintenance costs for a bus that is 7 years old? Part (e) (2 points) Is the estimate of the coefficient on the "Age" variable statistically significant? Please answer "yes" or "no" and explain how you can tell. Part (f (2 points) What percentage of variation in maintenance cost cannot be explained by variation in the age of the buses? Part (g) (2 points) If instead of regressing "Maintenance cost per month" on "Age" as in Part (a), we regressed "Age" on "Maintenance cost per month" instead, would R-Squared be the same as in the regression in Part (a)? Justify your answer. Part (h) (2 points) If instead of regressing"Maintenance cost per month" on "Age" as in Part (a), we regressed "Age" on "Maintenance cost per month" instead, would the estimate of the slope coefficient be the same as in the regression in Part (a)? Justify your answer. Part (i) (2 points) Would it make sense to claim that there is causation going from "Maintenance cost per month" to "Age," i.e., is there a "story" we can tell that would explain why changes in the maintenance cost of buses would plausibly have an impact on the age of buses. Page 1 of 2

Explanation / Answer

SUMMARY OUTPUT

Regression Statistics

Multiple R

0.663697769

R Square

0.440494729

Adjusted R Square

0.432017376

Standard Error

44.67702904

Observations

68

ANOVA

df

SS

MS

F

Significance F

Regression

1

103716.7836

103716.7836

51.9613552

6.89154E-10

Residual

66

131738.437

1996.036924

Total

67

235455.2206

Coefficients

Standard Error

t Stat

P-value

Lower 95%

Upper 95%

Intercept

362.3907162

14.82172619

24.44996701

8.51653E-35

332.7981851

391.9832474

Age

13.18212728

1.828711795

7.208422518

6.89154E-10

9.53098638

16.83326818

b)

As a general concept, as the age of the vehicle increases, the maintenance cost of the same is bound to go up.

c)

13.18. This means that for every increase of 1 in age, the maintenance cost would go up by 13.18 all other factors remaining constant.

d)

y=362.39+13.18x=362.39+13.18(7)=454.65

e)

Yes. Because p-value is less than 0.05

f)

1-0.44=0.66 or 66%

SUMMARY OUTPUT

Regression Statistics

Multiple R

0.663697769

R Square

0.440494729

Adjusted R Square

0.432017376

Standard Error

44.67702904

Observations

68

ANOVA

df

SS

MS

F

Significance F

Regression

1

103716.7836

103716.7836

51.9613552

6.89154E-10

Residual

66

131738.437

1996.036924

Total

67

235455.2206

Coefficients

Standard Error

t Stat

P-value

Lower 95%

Upper 95%

Intercept

362.3907162

14.82172619

24.44996701

8.51653E-35

332.7981851

391.9832474

Age

13.18212728

1.828711795

7.208422518

6.89154E-10

9.53098638

16.83326818