DU Assignment 3A, Ch 3 PDF

Preview

Summary

Download DU Assignment 3A, Ch 3 PDF

Description

Assignment 3A (The Great Plains Railroad) Chapter 3 Topics: Correlation and Linear Regression The Great Plains Railroad is studying how fuel consumption is related to the number of railcars for its trains on a certain route between Oklahoma City and Omaha. A random sample of 10 trains on this route has yielded the data in the table below. Train Number of Fuel Consumption # Railcars (units/mile) 1 20 58 2 20 52 3 37 91 4 31 80 5 47 114 6 43 98 7 39 87 8 50 122 9 40 100 10 29 70 Answer each question in the space provided. 1a.

Which variable is the explanatory variable? ____________________________

1b.

Which variable is the response variable? _______________________________

2.

Use https://www.stapplet.com/ (Two Quantitative Variables) to construct a scatterplot. Be sure your axes are appropriately labeled. Check your scatterplot against the scatterplot shown on the following page.

3.

Describe the relation between the number of railcars and fuel consumption. Be sure to address strength, direction, and form in the context of the exercise.

4.

From your output, write the correlation: __________________ . Interpret the correlation.

5.

Write the equation of the least-squares regression line using the manner in which you have been instructed.

6.

Interpret the slope of the regression line in the context of this exercise.

7.

Interpret the y-intercept in the context of this exercise.

8.

Use the regression line to predict the fuel consumption for train #5 (the train with 47 railcars). Then calculate the residual value.

9.

Explain why the model should not be used to predict the fuel consumption for a train with 80 railcars.

10. Use https://www.stapplet.com/ to construct a residual plot. Check your residual plot against the residual plot shown below. 11. Describe how the residual plot supports the use of a linear model for these data. 12. From your output, write the coefficient of determination: __________________ . Interpret this value. 13. From your output, what is the value of s? Interpret the value of s. This number is the standard error of the residuals....