A major oil company is studying relationship between the daily traffic count and the number of gallons of gasoline pumped at company stations. A sample of eight company owned stations is selected and the following information obtained.
Location Total Gallons of Gas
Pumped Traffic Count of Vehicles
West St. 120 4
Willouhby St. 180 6
Mallard Rd. 140 5
Pheasant Rd. 150 5
I-75 210 8
Kinzua Blvd. 100 3
Front St. 90 3
Indiana Ave. 80 2
a. Develop a scatter diagram with the amount of gasoline pumped as the dependent variable (by computer).
b. Compute the coefficient of correlation (by hand and by computer).
c. Compute the coefficient of determination (by hand and by computer).
d. Interpret the meaning of the coefficient of determination.
e. Test to determine whether the correlation in the population is zero, versus the alternate hypothesis that the correlation is greater than zero. Use the 0.05 significance level (by hand).