Question

What is the standard deviation of this data to the nearest one hundredth?

10 12, 8, 2

Answer 1

whats the mean?

Answer 2

8

Answer 3

subtract 8 from every data point .. whats the set we get?

Answer 4

2, 4, 0, -6

Answer 5

good, now square those values

Answer 6

How?

Answer 7

n^2 = n*n

Answer 8

Multiply each number with itself

Answer 9

the longest part is simply finding the sum of the squares of the differences from the mean ....

Answer 10

step 1; find the mean of the set

step 2; subtract the mean from the set

step 3; square the results

step 4; find the mean of the squares (if its a population), or use n-1 for a sample

the result of this is called variance.

the sqrt(variance) equals standard deviation

Answer 11

Ok i'm confused on the last step

Answer 12

2, 4, 0, -6 ; square these values

2^2, 4^2, 0^2, (-6)^2 ; what do we get to work with?

Answer 13

4, 16, 0, -36

Answer 14

-6 * -6 = 36 the idea is to have all positive values

now considering that the data set is a population, and not a sample of a population .... what is the mean of the squares?

Answer 15

14

Answer 16

then the variance is 14

standard deviation is the sqrt of variance soooo

sqrt(14) = ??? rnd it as they desire

Answer 17

Ok thanks

Answer 18

suppose this was a sample from a given population .... such that the population had 32 data points.

that mean of the squares would be refering to a sample (of size 4) of the population and we would need to divide by: 4-1

but thats just insight into a different question

Answer 19

How do you round 14 to the nearest hundreth then?

Answer 20

*one hundreth

Answer 21

what do you get as the sqrt(14) ?

Answer 22

14?

Answer 23

or 196?

Answer 24

\[\sqrt{14}=??\]

Answer 25

im assuming you know how to operate a calculator for this

Answer 26

if not, type: sqrt(14) into a google search

Answer 27

3.741?

Answer 28

yep, the "hundreths" spot is 2 decimals

Answer 29

so, 3.74 is fine

Answer 30

ok thanks

Answer 31

youre welcome