Question

how do i figure out the standard deviation of population

Answer 1

You have your numbers.....that's called your "data"
1. Find the mean of the data.
2. For each number,X, in your data, calculate: (X - mean)^2
3. Add up the answers to # 2 for each X and divide the total by n...the number things in your data
4. Take the square root of your answer to 3.

Answer 2

lets see if i got this right for my numbers they are as follows
40
40
40
40
0
54
40
0
4
mean for all these numbers is 28.7
so i calculate 40 x 28.7 to get my first number
then i add all the numbers up at the end

Answer 3

oops i calculate 40x28.7^2

Answer 4

The mean is actually 28.666666.... Don't round when you're calculating this. Just keep it in your calculator.
For number 2 you have to calculate, for ALL of your data
(40 - 28)^2
(40 - 28)^2
(40 - 28)^2
(40 - 28)^2
(0 - 28)^2
(54 - 28)^2
(40 - 28)^2
(0 - 28)^2
(4 - 28)^2
And add up all of those answers. It's a pain, i know! Most people use technology of some sort to calculate this. You shouldn't have to do it all by hand like this. Do you have a standard deviation function on your calculator?

Answer 5

All those 28's above should really be 28.6666666666..

Answer 6

(40 - 28)^2=144
(40 - 28)^2=144
(40 - 28)^2=144
etc
like this

Answer 7

\[\sigma=\sqrt{\frac{ \sum_{k=1}^{n}\left( x_k-\mu \right)^2}{n}}\]

Answer 8

you can do it in excel or on paper
if on paper, make a table as it's easier to keep track

Answer 9

The Standard Deviation is a measure of how spread out numbers are.

Answer 10

you still having trouble?

Answer 11

Yes I am

Answer 12

Data ID would be
1 2 3 4 5 6 7 8 9
x= 40 40 40 40 0 54 40 0 4

so far am i right

Answer 13

5-40, 2-0, 1-4 and 1-54... yeah?

Answer 14

and the average is?

Answer 15

what kind of calculator do you have?

Answer 16

just the one on the computer it has the scientific calculator

Answer 17

do you have excel?

Answer 18

yeah i do

Answer 19

list your data in a column. then i can show you the easy way and the rigorous way both

Answer 20

i got it the standard deviation for population is 19.821425

Answer 21

but what i need to do is show my work how do i do that

Answer 22

you can do that in excel.

so dod you list your data in a column?

Answer 23

did

Answer 24

the next cell down (after your data) in the column, type =avg and functions should appear. click on average

Answer 25

i did i put all the numbers and hit the Standardize P and it gave me that for answer

Answer 26

i understand but you said you had to show your work, right?

Answer 27

yeah here is the question

Using the data collected in Week 2, perform the following:

Calculate the z-scores for each subject for two variables—hours worked per week and satisfaction with income.
Compute the mean and the standard deviation for the population for the two variables.
Starting with the z-score formula, show all the steps of the calculations for the z-scores for each variable.
On the basis of your calculations, describe for each subject how you would interpret any potential relationships between the number of hours worked per week and the subject's satisfaction with his or her income.
Starting with the formula and substituting values for each variable, provide all the steps of the calculations to arrive at a z-score of +1.4. Show all steps of

Answer 28

\[z=\frac{( x-\mu) }{\sigma }\]

Answer 29

it doesn't say you have to show the work for the std dev

Answer 30

oops i read it wrong lol

Answer 31

lol you got it then?

Answer 32

\[z=\frac{ (x-\mu) }{ \sigma}\] can u refresh me on this here is what i have


name Hours worked Satisfaction w/ inc zhours zincome
Debbie 40 4 0.53907 0.27217
Jeff 40 3 0.53907 -0.54433
Phil 40 2 0.53907 -1.36083
Glen 40 2 0.53907 -1.36083
Ionita 0 3 -1.36353 -0.54433
Gregg 54 5 1.20498 1.08866
Roy 40 5 0.53907 1.08866
Bobbie 0 4 -1.36353 0.27217
Theresa 4 5 -1.17327 1.08866

Answer 33

for 40 i get .57177 for a z-score
for 0 i get -1.446 for a z-score
for 4 i get -1.244 for a z-score
for 54 i get 1.2871 for a z-score
on hours worked

Answer 34

i calculated this on mini tab

Answer 35

what was your std dev?

Answer 36

you used the sample std dev. i thought you were supposed to use the pop. std. dev...

Answer 37

the standard deviation i did on excell and i did population the z score i did on mini tab can you do z score on excel

Answer 38

if so how do you do it never used excel for this

Answer 39

yeah. hold on a sec...

Answer 40

k

Answer 41

=(A2-AVERAGE($A$2:$A$10))/STDEV.P($A$2:$A$10)

the data is in cells A2 to A10

the $ fix the references so the don't move as you darg to copy the formula.

once you do that for the hours you can replace the data withthe satisfaction data and leave the formulas there and voila!

Answer 42

also, you can use a fucntion... hold on a sec.

Answer 43

nevermind. the fucntion gives the probability, not the z-score.

Answer 44

good luck! i have to go. c ya!

Answer 45

thank you so much