To any math, engineering, or other worth folks:

I am very rusty on my statistics and was trying to come up with a way to illustrate standard deviation as simply as possible. I was thinking that t-scores were mean=50 with sd=10 and that this represented a perfect distribution. So, to illustrate, I was going to theorize that we have a test on which a person could score between 1 and 100. Now supposing that the test was so good it came out so that one person scored 1, two people scored 2, and so on so that 50 people scored 50, 49 scored 51 and so on until we get to that one person at the head of the class who scored 100. I figured the n which is 2468 (I believe). But, when I did the math, the number of test takers scoring between 40 and 60 did not come out to the correct sd proportion of 68+% of the sample.

Where did I go wrong? Also, if you have a calculator, a computer program, or are laughing at me for not having such a rudimentary figure in my head, could you tell me what the sd WOULD be with this perfect distribution?

W. Ed Smith, Ph.D.
Psychologist and Clinical Services Coordinator 
Counseling and Career Planning Center
University of Tennessee at Chattanooga
615 McCallie Ave.
Chattanooga, TN  37403

423 425-4438


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