Question

What is the standard deviation of the following data? If necessary, round your answer to two decimal places.
10, 12, 15, 18, 11, 13, 14, 16, 19, 20

Answer 1

we can make the adding simpler by subtracting 10 from each to begin with; all that does is shift the values and retains the spread

Answer 2

0,2,5,8,1,3,4,6,9,10

sums to 48? and there are 10 of them so mean = 48/10 = 4.8

Answer 3

find the difference of each point from the mean; and square the results

0, 2 ,5 ,8, 1, 3, 4, 6 , 9, 10
-4.8
----------------------
4.8, 2.8, .2, 3.2, 3.8, 1.8, .8, 1.2, 4.2, 5.2

square em, and add em up

Answer 4

4.8^2+ 2.8^2+ .2^2+ 3.2^2+ 3.8^2+ 1.8^2+ .8^2+ 1.2^2+ 4.2^2+5.2^2 = 105.6

http://www.google.com/search?aq=f&ix=acb&sourceid=chrome&ie=UTF-8&q=4.8%5E2%2B+2.8%5E2%2B+.2%5E2%2B+3.2%5E2%2B+3.8%5E2%2B+1.8%5E2%2B+.8%5E2%2B+1.2%5E2%2B+4.2%5E2%2B5.2%5E2

Answer 5

thats the hard parts lol

Answer 6

next is to determine if we divide this by N or N-1

if these data points are a population; divide by N .... 10 in this case

if these data points are a sample; divide by N-1 .... or 9 in this case

then square root the result of that and you have the sd

Answer 7

if there was a mode value, you could have subtracted that at first to get a few of the terms to zero out at the onset; or if you use the median value to subtract from that then you can get your mean calculations even closer to zero

Answer 8

Okay

Answer 9

So. what is the standard deviation of this question?

Answer 10

well, if my head math was good ... this will be one of two sds

population: sqrt(105.6/10)

sample: sqrt(105.6/9)

with any luck, if youve got choices to pick from you can narrow it down form there

Answer 11

Oh okay
thanks for the help :)

Answer 12

good luck ;)