Homework: Frequencies

The focus of this homework is give you practice in using the frequencies procedure to identify shapes of distributions.

Run the frequencies procedure on each of the nine Computer Knowledge questions (unix commands, emacs commands, ms-dos commands, word processing on a pc, programming language, how to use Widows 95, how to use spreadsheets, run SPSS on a mainframe, and run SPSS for windows).

1. Suppress the output of the frequencies tables (1 pt)
2. Create a histogram with a superimposed normal distribution for each of the nine variables (2 pts)
3. Display only the following statistics for each of the nine variables: mean, standard deviation, skewness, standard error of skewness, kurtosis, and standard error of kurtosis. (1 pt)
4. Save all the above output in a single file called freqxxx.spo, where xxx are your initials (e.g., freqlab.spo). Turn in your disk with that file.

5. Fill out the table below by
a) entering the 95% confidence intervals for skewness and kurtosis for each of the variables. Round each value to 3 decimal places. Note: 95% confidence intervals should range from the lowest to the highest value. (4 pts)
b) check the correct distribution shape for each of the variables. (4 pts)
6. Turn in a printed copy of this page.

Question: knowledge of ...	normal?	skewness?	kurtosis?
unix commands	___ yes ___ no	95% CI: ______ to ______ ___ pos skew ___ no skew ___ neg skew	95% CI: ______ to ______ __ leptokurtic __ no kurtosis __ platykurtic
emacs commands	___ yes ___ no	95% CI: ______ to ______ ___ pos skew ___ no skew ___ neg skew	95% CI: ______ to ______ __ leptokurtic __ no kurtosis __ platykurtic
how to use spreadsheets	___ yes ___ no	95% CI: ______ to ______ ___ pos skew ___ no skew ___ neg skew	95% CI: ______ to ______ __ leptokurtic __ no kurtosis __ platykurtic
run SPSS for Windows	___ yes ___ no	95% CI: ______ to ______ ___ pos skew ___ no skew ___ neg skew	95% CI: ______ to ______ __ leptokurtic __ no kurtosis __ platykurtic