# Measures of Central Tendency & t-86

The statistics course I'm taking is a technology based course, & goes hand in hand with the ti-83. I happened to have a ti-86 & need some help.

I understand how to calculate the mean by hand & by the calculator for most circumstances. What I don't is when there are classes, for example

Class Frequency
10-19 8
20-29 16
30-39 21
40-49 11
50-59 4

Now, I can compute the approximate mean by hand with the formula in the book. The answer gives a mean = 32.83 & a standard deviation = 11.06. The answer checks with the back of the book. How can I place this information into the ti-86 & get the same results?

## Answers and Replies

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You will have to enter a list. To solve the following problem, Enter a list of 8 15s 16 25s 21 35s etc. Then you can pull all the 1-Var Stats of this list. It should give you the proper mean, and variance.

Thanks for the help, what actually happened was I was getting the xstat & ystat mixed up with fstat... The classes as you pointed had to be placed in the xstat & then the frequency in the fstat. Seems kinda silly, not sure why I didn't get it before.