Deriving the regression equation, testing the model fit and obtains confidence interval for estimated values.
The Apex Corporation produces corrugated paper. It has collected monthly data from January 2001 through March 2003 on the following two variables:
y, total manufacturing cost per month (in thousands of dollars) (COST)
x, total machine hours used per month (MACHINE)
Data shown below: make any analysis necessary to answer the following problems:
1. What is the approximate regression equation relating y to x?
2. What percentage of the variation in y has been describeed by the regression?
3. Are y and x linearly related? Conduct a hypothesis test to answer this problem and use a 5% level of significance. State the hypotheses to be tested, the decision rule, the test statistic, and your decision. What conclusion can be drawn from the result of the test?
4. Apply the equation developed to estimate the average manufacturing cost in a month with 350 machine hours. Find a point estimate and a 95 percent confidence interval estimate. How reliable do you believe this forecast might be?
5. Employ the equation developed to estimate the average manufacturing cost in a month with 550 machine hours. Find a point estimate and a 95 percent confidence interval estimate. How reliable do you believe this forecast might be?
COST

MACHINE

1102

218

1008

199

1227

249

1395

277

1710

363

1881

399

1924

411

1246

248

1255

259

1314

266

1557

334

1887

401

1204

238

1211

246

1287

259

1451

286

1828

389

1903

404

1997

430

1363

271

1421

286

1543

317

1774

376

1929

415

1317

260

1302

255

1388

281
