Question

Please help (Statistics Course)
Find the range, mean, variance, and standarda deviation of the sample data set
13 5 11 20 10 17 15 8 19

I have worked out the range and mean
Range: 15
Mean: 13.1

I am having difficulty finding variance and standard deviation

Answer 1

yeah, do the easy parts and leave the hard stuff for last :)

Answer 2

\[variance=\frac{\sum (x-\bar x)^2}{n}\]
maybe

Answer 3

and sd is sqrt(vars)

Answer 4

variance is 25.86
standard deviation is 5.09

Answer 5

13 5 11 20 10 17 15 8 19


13' 1/9 means good
--------
9)118
9
---
28
27

Answer 6

Juanita how did you get to that. Amis...I looking over what you have. Let me see if I understand it

Answer 7

http://www.wolframalpha.com/input/?i=13%2C++5%2C++11%2C++20%2C++10%2C++17%2C++15%2C++8%2C++19

variance = (sd)^2

Answer 8

subtracting that fraction is a nightmare to try to type up something sensible in here

Answer 9

but in essense; you subtract the mean from each data point

square the results

add up those result

and divide by how many data points there are

Answer 10

thats variance; then square root it for standard deviation

Answer 11

a sample is almost the same except for you use a degree of freedom; instead of dividing off the lot by "n"; you do it by "n-1" for a sample

Answer 12

I still don't get it. I am going to write what you typed in a mathematical format. Thanks.

Answer 13

well, good luck with it :)