Question

FANN & MEDALL

1. Find the standard deviation of 4,8,5,12,3,9,5,2

Answer 1

did you find the mean yet?

Answer 2

\[\frac{4+8+5+12+3+9+5+2}{8}=?\]

Answer 3

that would be the mean

Answer 4

the mean is 6

Answer 5

right?

Answer 6

@xapproachesinfinity

Answer 7

yes

Answer 8

now each number subtract the mean from it and square it

Answer 9

4-6=-2
(-2)^2=4
8-6=2
2^2=4
and continue

Answer 10

we are trying the find the variance

Answer 11

okay... hold on

Answer 12

did you do it?

Answer 13

5-6=-1
(-1)^2=-1
12-6=6
(6)^2=36
3-6=-3
(-3)^2=-9
9-6=3
(3)^2=9
5-6=-1
(-1)^2=-1
2-6=-4
(-4)^2=-16

Answer 14

right? @xapproachesinfinity

Answer 15

(-1)^2=1 not -1
(-3)^2=9 not -9
same for the rest

Answer 16

when you square a number negative vanishes

Answer 17

so we got 4,4,1,36,9,9,1,16
now we need to find the mean for this numbers

Answer 18

see how i found the mean for the first step

Answer 19

yes... do i find it for those numbers now?

Answer 20

yes

Answer 21

okay.. hold on

Answer 22

10?

Answer 23

yes

Answer 24

now take the square root of that

Answer 25

3.16?

Answer 26

@xapproachesinfinity

Answer 27

is that gonna be the answer?

Answer 28

yes

Answer 29

thxx so much!!! :)

Answer 30

no problem