4. Computer Problem for Problem Set 5
Use the SSAE98 data set (in folder t:\students\public\201) to obtain the following. Print out the results for the a. parts of each question and write the answers to the b. parts on the printout. Alternatively, use Copy objects to move the tables into a Word for Windows file, write the answers to the b. parts there, and then hand in.
1. a. Obtain 95%, 90%, and 99% interval estimates for the household income of students in the survey. In order to do this, use Analyze-Descriptive statistics- Explore and place income in the Dependent List. Before clicking OK, click Statistics on Display, so you obtain only the relevant statistics and not the stem-and-leaf display. This will provide the 95% per cent interval. For the 90% and 90% interval estimates, after putting income in the Dependent List, click on the Statistics box at the middle bottom and change the confidence level. b. (i) Show how one of the intervals is obtained – that is, use the reported mean and standard deviation and, using the formulas from the text or class, show how the interval estimate is calculated. (ii) From the Statistics Canada Survey of Labour and Income Dynamics (SLID), the mean income of Saskatchewan households with two or more persons was $53,378 in 1998. From the interval estimates of a., does it appear that students come from households different than the provincial average? Comment using the interval estimates.
2. a. Obtain 95% interval estimates of study hours, extracurricular hours, and hours spent caring for dependents, for each of males and females. You can do this in the same way as 1.a., but this time using sex of respondent in the Factor List. b. In an earlier problem set, you examined these same variables using the means procedure, but without obtaining interval estimates. Do the interval estimates support your earlier conclusions? Comment.
3. a. Use Analyze-Compare Means-One-Sample T-test to conduct two tests of a mean. Test whether the mean grade of all undergraduates equals (i) 75%, and (ii) 74%. b. Explain your findings in a.
4. Test whether the true mean household income of students equals the Saskatchewan mean reported in question 1.a. b. Explain whether the finding from the hypothesis test are consistent with the interval estimates of question 1.