Dana Corp. uses linear regression to estimate costs. The machine hours and related costs for the last year, as well as the regression analysis results, are as follows:

Month Maintenance Cost Machine Hours

Jan. $4,450580

Feb.3,250420

Mar.3,850500

Apr.3,070400

May4,600600

June3,210410

July3,280420

Aug.4,720620

Sept.4,510590

Oct.4,300570

Nov.3,550450

Dec.3,410440

Sum$46,2006,000

Average$3,850$500

Average cost per hour$8.00a (intercept)$205.82b (coefficient)7.2884Standard error of the estimate34.469R-squared0.99724t-value for b60.1050

If machine hours are 400, Aaron's manager can be approximately two-thirds confident that the range of the maintenance costs will be

Multiple Choice

• $3,060.72 to $3,181.61.
• $3,059.74 to $3,182.62.
• $3,086.71 to $3,155.65.
• $3,095.43 to $3,147.05.
• None of these answer choices are correct.