According to the National Automobile Dealers Association, themean price for used cars is $10,192. A manager of a Kansas Cityused car dealership reviewed a sample of 50 recent used car salesat the dealership in an attempt to determine whether the populationmean price for used cars at this particular dealership differedfrom the national mean. The prices for the sample of 50 cars areshown.
| Sale Price |
| 12400 |
| 10400 |
| 12100 |
| 10000 |
| 11000 |
| 8895 |
| 7675 |
| 9975 |
| 6350 |
| 10470 |
| 9895 |
| 11250 |
| 8795 |
| 12500 |
| 9340 |
| 10150 |
| 9200 |
| 9395 |
| 11000 |
| 10640 |
| 10000 |
| 7500 |
| 8000 |
| 10440 |
| 10200 |
| 10300 |
| 9740 |
| 9280 |
| 10930 |
| 8000 |
| 9000 |
| 7680 |
| 9400 |
| 10730 |
| 7350 |
| 12240 |
| 11970 |
| 8240 |
| 9910 |
| 10080 |
| 9440 |
| 8970 |
| 9500 |
| 10050 |
| 10130 |
| 11400 |
| 8500 |
| 7500 |
| 9090 |
| 10500 |
- Use Excel’s Data Analysis to get the descriptivestatistics for sale price.
- Construct a 95% confidence interval for the population meansale price for the dealership.
- Formulate the hypotheses that can be used to determine whetherthe population mean price for used cars at this particulardealership differed from the national mean. Conduct the test usingthe critical value approach and α=0.05.
- Use Excel function =t.dist.2t to findthe p-value in the preceding hypothesis test and constructthe test with the p-value approach.
- Formulate hypotheses that can be used to determine whether thepopulation mean price for used cars at this particular dealershipis less than the national mean. At α=0.05, can your nullhypothesis be rejected? What is your conclusion? Conduct the testusing the critical value approach.
- Use Excel function =t.dist to findthe p-value in the preceding hypothesis test and constructthe test with the p-value approach.
