A marketing company, interesting in promoting fireworks, has noticed an increase in the amount of fireworks purchased. They obtained data on firework usage (millions of pounds) from 1990 to 2001. Time...

A marketing company, interesting in promoting fireworks, has noticed an increase in the amount of fireworks purchased. They obtained data on firework usage (millions of pounds) from 1990 to 2001. Time is measured in years since 1990, thus the year 1990 was recorded as year 0. They fit a least squares regression line to the data. The graph of the residuals and part of the computer output for their regression are given below.

a) Is a line an appropriate model to use for these data? What information tells you this?

b) What is the value of the slope of the least squares regression line? Interpret the slope in the context of this situation.

c) What is the value of the intercept of the least squares regression line? Interpret the intercept in the context of this situation.

d) What is the predicted amount of fireworks used in 1998?

e) What is the actual fireworks used in 1998?

Extracted text: 15 10 5 -5- -10. -15- -20 2 4 6 8 10 12 Years_Since_1990 Std P Predictor Coefficient Error Statistic Value AR? Constant 72.7860 7.9731 9.129 0.0001 Years_Since_1990 8.1875 1.1708 6.993 0.0004 0.8907 Residual