Imagine that you are the statistical consultant for a firm that is designing blouses for a population of women it has not previously served. They have asked you to gather the relevant statistics to describe the distribution of chest circumferences in this population. You obtain a random sample of 100 such measurements. Your data are deposited in my SimData directory on the core server. You can jump directly to your data file by clicking below on the link with your name. It will have a name of the form 'BLOUSES-nn,' where 'nn' is the identification number I use to identify your data files. Your assignment is to use SAS to obtain the appropriate descriptive statistics.

1. Obtain a frequency distribution table for your sample data. This is easily done by including the FREQ option in PROC UNIVARIATE -- for example, Proc Univariate Freq Plot; Var Circumference;.

2. Obtain a stem & leaf plot and a box plot.

3. Obtain the mean, sample standard deviation, median, and mode and report each of them in your report.

4. Describe the SHAPE of the distribution from which your sample was likely to have been randomly obtained (appropriate terms might include "approximately normal," "symmetric," "skewed" (identify in which direction), "uniform" ("rectangular"), "bimodal," "U," etc. Refer to the appropriate statistics and plots that support your description of the shape of the distribution.

5. Your boss tells you that she wants to market blouses that will fit the middle 50% of the distribution. From your sample data identify the middle 50% of the distribution (the two points between which the middle 50% of the scores fall).

6. Prepare a Microsoft Word document in which you summarize the results of the analysis.  On the first line of the document type your name.  Please use a 12-point font, preferably Arial.   Prepare a table, like that below, in which you report the indicated statistics to two or three decimal points, like this:

   Statistic	Value
   Sample Size (N)	100
   Mean	34.93
   Median	35
   Mode	34
   Standard Deviation	2.99
   Shape*	symmetric, nearly uniform
   Skewness	-0.0006
   Middle 50%	32.5 to 37.5

       *Indicate whether the distribution is symmetric (or nearly so) or not, and whether it appears to be from a population that is uniform, normal, bimodal, U-shaped, or quite skewed.

       Do not expect me to fish for the requested statistics in your SAS output.  You do the fishing and put your catch in the table formatted like that above.

7.    After the table, insert the SAS commands you used to produce the output.

8.    At the bottom of the document, insert your SAS output.  Be sure that you have adjusted the margins so that the lines do not wrap.

9.    Name the Word document "Nnnnnn_Blouses.xxx" where "Nnnnnnn" is your last name and "xxx" is the extension (doc or docx).

10.    Attach the Word document to mail sent to wuenschk@ECU.edu.  Use a subject line of "PSYC 6430:  Descriptives Homework."

11.    To receive full credit on this assignment, your report must be received no later than noon on TBA.

    If you are using the Internet Explorer, to download the file you should point at your name and then RIGHT CLICK on the mouse. You will get a drop down menu. From that menu select "Save Target As" and then point at the drive/folder where you wish to store the data file. 

Use your browser's BACK key to return to the page you previously visited or use one of the following links.

•  Read a document about shapes of distributions -- should help you complete this assignment.

•  How Properly to Format the Document -- please follow the guidelines presented in this document.

•  Thesis Errors -- do not make any of the errors described in this document

•  Visit Karl's SAS Programs Page -- find an example (INTROQ1.sas) of how to do basic descriptive statistics.

•  Visit Karl's Index Page -- search for other information on Karl's pages

•  Visit the PSYC 6430 base page

Contact Information for the Webmaster,
Dr. Karl L. Wuensch

This page most recently revised on 27. August 2009.