**Fall 2003**

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**4. Computer Problem for Problem Set 5**

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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.