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e How a regression line summarizes a scatterplot . How the regression equation i

ID: 3060386 • Letter: E

Question

e How a regression line summarizes a scatterplot . How the regression equation is used to predict the Y scores at a given How the standard error of the estimate measures the errors in prediction Jesse's friend, Marty, thinks that another good predictor of time taken to reach the finish line for a 1- mile race on dirt would be the difference between the jockey (rider) and horse's weight. Therefore Marty tracks 5 horses over 5 1-mile races on dirt, recording the average difference between the weigh of the horse and Jockey (horse weight-Jockey weight) and the time (in seconds) it took the horse to reach the finish line. His data is summarized below Horse Average weight difference in lbs. (x) Average finish time in seconds (Y) 891.69 889.92 891.32 892.04 884.2 104.33 102.32 97.04 95.63 104 48 What is the strength and direction of the relationship between the average weight difference and time taken to reach the finish line? 6. 7. Using the appropriate regression equation, what is the predicted finish time for a horse that weighs 893 Ibs. more than its jockey? 8. What is the standard error of the estimate of Marty's data? 9 How much of the variance in the average time taken to reach the finish line for a 1-mile race on dirt is accounted for by variance in weight difference?

Explanation / Answer

Result:

6). The correlation between average weight difference and time taken to reach the finish line is

-0.574.

The relation is negative and strength s moderate.

7).

The regression line is

Average finish time = 754.2741-0.7344*average weight difference.

When average weight difference = 893,

Predicted Average finish time = 754.2741-0.7344*893

=98.4549

8). standard error = 3.932

Regression Analysis

0.330

n

5

r

-0.574

k

1

Std. Error

3.932

Dep. Var.

y

ANOVA table

Source

SS

df

MS

F

p-value

Regression

22.7988

1  

22.7988

1.47

.3114

Residual

46.3734

3  

15.4578

Total

69.1722

4  

Regression output

confidence interval

variables

coefficients

std. error

   t (df=3)

p-value

95% lower

95% upper

Intercept

754.2741

538.1159

1.402

.2556

-958.2509

2,466.7991

x

-0.7344

0.6047

-1.214

.3114

-2.6590

1.1901

Regression Analysis

0.330

n

5

r

-0.574

k

1

Std. Error

3.932

Dep. Var.

y

ANOVA table

Source

SS

df

MS

F

p-value

Regression

22.7988

1  

22.7988

1.47

.3114

Residual

46.3734

3  

15.4578

Total

69.1722

4  

Regression output

confidence interval

variables

coefficients

std. error

   t (df=3)

p-value

95% lower

95% upper

Intercept

754.2741

538.1159

1.402

.2556

-958.2509

2,466.7991

x

-0.7344

0.6047

-1.214

.3114

-2.6590

1.1901