Exam 1 Review

Inferences from 2 samplesANOVA

Nonparametrics

Review 1

• A consumer group is testing the gas mileage of 3 different models of cars. Several cars were driven 1000 miles and the gas mileage was recorded in the following table.

• Data is in the Cars_practice data set.• Use • What is the:– Null hypothesis?– Alternative hypothesis?– Conclusion?

Review 1

Model 1 Model 2 Model 322.6 19.6 25.320.9 22.3 21.623.6 20.5 20.521.9 17.0 24.622.0 17.6 22.721.1 19.2 20.518.7 20.9

Review 2

• An analyst is looking at two portfolios of common stocks in terms of the average price-earnings ratio. He wishes to determine if there is a difference between the two portfolios.

Portfolio 1 Portfolio 2

Review 2

• Perform the appropriate test and provide:– Null hypothesis– Alternative hypothesis– Conclusion

• Use • Construct a 95% confidence interval of the

difference between the two portfolios.

Review 3

• A new SAT preparation program claims that students will improve their verbal scores with a practice test after one month on the program. To validate their claim, they recorded the starting and practice verbal SAT scores of 12 individuals after a one-month period.

Review 3Starting SAT Score Practice SAT Score

450 460

390 390

425 430

510 500

520 525

440 420

550 570

610 625

490 510

475 485

535 540

500 500

• Use an alpha of .05• What is the

appropriate test?• What is:• The null

hypothesis• The alternative

hypothesis• The conclusion

• SAT data set is online

Review 4

• From the top 1000 companies in valuation, a comparison of the mean dividend yield of the top and bottom ten electric utility companies is desired. The data shown below are for two independent samples, which are drawn at random from populations that are normally distributed.

Review 4

• Also in data set as Electric_practiceTop Ten Bottom Ten

8.76 6.658.96 6.387.20 6.248.92 6.938.61 7.467.81 0.006.58 7.788.06 8.64

6.42 7.356.64 7.33

• Alpha = .05• Null hypothesis• Alternative hypothesis• Conclusion