# deviation

• Sep 12th 2007, 01:32 PM
harry
deviation
For the following scores, find the (a) mean, (b) median, (c) sum of squared deviations, (d) variance, and (e) standard deviation:

2, 2, 0, 5, 1, 4, 1, 3, 0, 0, 1, 4, 4, 0, 1, 4, 3, 4, 2, 1, 0
• Sep 12th 2007, 01:37 PM
Jhevon
Quote:

Originally Posted by harry
For the following scores, find the (a) mean, (b) median, (c) sum of squared deviations, (d) variance, and (e) standard deviation:

2, 2, 0, 5, 1, 4, 1, 3, 0, 0, 1, 4, 4, 0, 1, 4, 3, 4, 2, 1, 0

i can help with (a) and (b), i should be able to help with (e), but i forgot the formula for the standard deviation. does anyone know an easy way to remember it? and the other formulas as well? i'm looking for any mnemonic that anyone might know.

(a) the mean is the average of all the numbers found in the following way:

$\mbox { Mean } = \frac {\mbox { Sum of all the numbers }}{ \mbox {The number of numbers there are }}$

(b) The median is the middle number when the list of numbers is arranged from lowest to highest. Note that if there is an odd number of numbers, the median is, in fact, the middle number. If there is an even number of numbers, the median is the mean of the two middle numbers
• Sep 15th 2007, 04:02 PM
ThePerfectHacker
Quote:

Originally Posted by harry
For the following scores, find the (a) mean, (b) median, (c) sum of squared deviations, (d) variance, and (e) standard deviation:

2, 2, 0, 5, 1, 4, 1, 3, 0, 0, 1, 4, 4, 0, 1, 4, 3, 4, 2, 1, 0

After you find the mean find the differences (deviation) from all these numbers squared. Add them up and that is (c).

Divide (c) by the number of numbers. That is (d).

Take the square root of (d) that is (e).