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### Computer Exercises: Estimation

(This exercise was give to work with Microsoft Excel and SPSS. It may be modified to work with other programs, and it may have to be modified to work with the current version of Excel and SPSS.)

How old do you think people on average when they die _______? (Fill in a number before you do anything else.)

Every week important people die, and obituaries are written about them. Several years ago 30 people who died had obits written about them in one of the issues of the Sunday Chicago Tribune. Here were their ages:

89.00 90.00 66.00 39.00 55.00
81.00 101.00 79.00 44.00 65.00
67.00 96.00 72.00 69.00 100.00
71.00 72.00 83.00 63.00 84.00
91.00 81.00 77.00 82.00 72.00
83.00 86.00 86.00 36.00 71.00

1. Enter these data into Excel and compute the mean __________, median __________, mode __________, range __________, and standard deviation __________. Save your results.

2. It is time to meet SPSS. Open the program, and see if you can open your Excel data into it. If not, retype it. You should have a column with 30 numbers. Click on the top of the column (which says var) and give your column a name (like age).

2. Once you have your 30 numbers, you can compute stuff. Pull down Statistics to Summarize to Descriptives. Move your variable over to the variable side (Highlight it, and then click the arrow). Hit Options and click on all the fun things you want to see. Hit Continue then OK. You will then see mean __________, and standard deviation __________.

3. Let's try some more. Pull down Statistics to Summarize to Frequencies. Move Age to the variable window, then click the statistics button. Click whatever you want, then click continue. The click the Charts button. Turn on the radio button for histogram and click on the "With Normal curve." Click continue, and then click OK. Are you impressed yet?

4. (Looking ahead--statistical inference). Pull down Statistics to "Compare Means" to "One Sample T Test." Enter the number from the top of this sheet (your guess as to the average age of death) in the test Value. Then hit OK. You will have no clue as to what these results mean, but you will once you understand hypothesis testing!!!

(Other sources of data that I used for course assignments on estimation and hypothesis testing were taken from Ebay, Facebook, and survey results that I was given. Trying to get what was cleary random samples from Ebay and Facebook was difficult and not completely satisfactory, but the assignments were fun for the students. The surveys were about things that were specific to the local campus and would not be of interest to others.)

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