SCENARIO 13-1
a Large National Bank Charges Local Companies for Using

SCENARIO 13-1
A large national bank charges local companies for using their services. A bank official reported the
results of a regression analysis designed to predict the bank's charges (Y) -- measured in dollars per
month -- for services rendered to local companies. One independent variable used to predict service
charges to a company is the company's sales revenue (X) -- measured in millions of dollars. Data for
21 companies who use the bank's services were used to fit the model: $$Y _ { i } = \beta _ { 0 } + \beta _ { 1 } X _ { i } + \varepsilon _ { i }$$
The results of the simple linear regression are provided below.
$$\hat { Y } = - 2,700 + 20 X , S _ { X X } = 65 , \text { two-tail } p \text { value } = 0.034 \left( \text { for testing } \beta _ { 1 } \right)$$
-Referring to Scenario 13-1, a 95% confidence interval for $\beta _ { 1 }$ is (15, 30) . Interpret the interval.

A) You are 95% confident that the mean service charge will fall between $15 and $30 per month.
B) You are 95% confident that the sales revenue (X) will increase between $15 and $30 million for every $1 increase in service charge (Y) .
C) You are 95% confident that mean service charge (Y) will increase between $15 and $30 for every $1 million increase in sales revenue (X) .
D) At the ? = 0.05 level, there is no evidence of a linear relationship between service charge (Y) and sales revenue (X) .