In: Statistics and Probability
kelly's blue book publishes data on new used cars. The following table contains the manufacturer's suggested retail price for four vehicles, model years 2006 and 2007. we are interested in the difference in price between the 2006 models and the 2007 models. Assume that the population of price differences is normally distributed.
Subaru Honda Toyota Nissan Forester CR-V RAV-4 Sentra |
|
2006 2007 |
$22,420 $20,990 $22,980 $13,815 $21,820 $22,395 $23,630 $15,375 |
use the mean of the differences, d=753.75, and the standard deviation of the differences, sd=986.1658
(a)Identify the null and alternative hypotheses to test whether 2007 models are on average more expensive.
(b) using level of significance a=0.05, find the test statistic and the critical value, and make your conclusion about the hypothesis test.
(c) construct and interpret a 95% confidence interval for us, the population mean difference in price.