Question

 

Freight car loadings over an 18-week period at a busy port are as follows:

Week	Tons loaded
1	220
2	245
3	280
4	275
5	300
6	310
7	350
8	360
9	400
10	380
11	420
12	450
13	460
14	475
15	500
16	510
17	525
18	541

The port manager wants build a model to forecast the loads for the remainder of the year.

a. Which variable is the dependent/response variable?

b. Which is the independent/explanatory variable?

Enter the data into your Excel file

c. Develop a scatterplot for these data. Interpret the scatterplot.

Run a regression analysis of the data on Excel using Data/Data Analysis

d. What is the correlation between Week and Tons loaded?

            What does it say about the strength of the relationship?

e. What is the coefficient of determination?

            How would you interpret it?

f. Write the hypotheses for the test of the slope.

g. What do you conclude about the slope of the line?

            What are you basing your conclusion on?

h. What is the regression formula that represents the relationship between Week and tons loaded?

i. Use your formula to predict the Tons loaded for Week 19.

j. Use your formula to predict the Tons loaded for Week 25.

Answer 1