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 'CIRCUM-nn,' where 'nn' is the identification number I use to identify your data files. Your assignment is to use SPSS to obtain the appropriate descriptive statistics. The data file is a plain text data file, with one column of scores. You will need to use the Read Text Data function of SPSS to bring these data into SPSS. Of course, you will first need to download your data file to the PC you are using.  When importing the data be sure to tell SPSS that the data are delimited, not fixed.  If SPSS thinks they are fixed format, it might not read the data correctly.

1. Obtain a frequency distribution table for your sample data. This is easily done by using the Frequencies procedure in SPSS. Use the Statistics button to request that SPSS compute the mode and the quartiles for you.

2. Use SPSS Explore to prepare a stem & leaf plot and a box plot .  Also obtain the mean, median, standard deviation, and skewness.

3. Describe the SHAPE of the distribution (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.

4. 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 (between what two points does the middle 50% of the scores fall).

5. 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:

    *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 SPSS output.  You do the fishing and put your catch in the table formatted like that above.

    Insert at the bottom of the document your SPSS output (see the link below regarding how to paste SPSS output into a Word document).

    Name the Word document "Nnnnnn_Circum.doc," where "Nnnnnnn" is your last name.

    Attach the Word document to mail sent to wuenschk@ECU.edu.  Use a subject line of "PSYC 2101:  Descriptives Homework."

    To receive full credit on this assignment, your report must be received no later than noon on Wednedsay the 27^th of May, 2009.

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 to the drive/folder where you wish to store the data file.

Please let me know if I should change your name from what is listed below - I may have made a typo, you prefer that I use a nickname, etc.

    Check out the interesting video at the Total Perspective Vortex link above.  Click OK on the first screen.

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.

• Copying SPSS Output Into a Word Document -- the most efficient way to package your SPSS output with interpretative text in a single file that can be attached to email.

• Visit Karl's SPSS Lessons Page -- learn or relearn how to do basic descriptive statistics with SPSS.

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

• Visit the PSYC 2101 base page
  

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



This page most recently revised on 21. May 2009.