Question

What is the standard deviation of the following data set? 5, 10, 8, 6, 11

a. square root 26
b. square root 10
c. square root 5.2
d. square root 6.5

Answer 1

i believe its:

subtract the mean from the data entries

square the results

add them up and divide by the number of entries (-1 for a degree of freedom)

then sqrt it

Answer 2

\[var=\frac{\sum(x-\bar x)^2}{n-1}\]

Answer 3

if this is a population then just divide by "n"

if its a sample of a population; then we do the degree of freedom

Answer 4

vqr = sd^2

sqrt(var)=sd

Answer 5

typos abound :)

Answer 6

so would it be c.?

Answer 7

dunno

Answer 8

amistre are you sure it's \( n-1 \) in the denominator?

Answer 9

on this one, i think itll go with the population and ot the sample; so we can just "n" the denom

Answer 10

im confused

Answer 11

and NOT the sample ..... my keyboard hates me

Answer 12

being confused is a rather vague and broad statement; how do we narrow it down?

Answer 13

first, find the mean by adding up all the data points and dividning by how many there are; in this case we have 5?

Answer 14

you need to determine if this is a sample or a population because the both answers are on the list

Answer 15

5+10+8+6+11 = 40

40/6 = 6 2/3 right?

Answer 16

if it helps, answer is d

Answer 17

opps, 40/5 = 8

mean would be 8

Answer 18

the answer is d ?

Answer 19

@zarkon, i missed that. what does it mean?

Answer 20

(5-8)^2 = 9
(10-8)^2 = 4
(8-8)^2 = 0
(6-8)^2 = 4
(11-8)^2 = 9
------------
added: 26

26/5 = variance

sqrt(variance) = sd

Answer 21

assuming population

Answer 22

the population std is c...the sample std is d

Answer 23

sqrt(5.2) is what i end up with if i did the mathing right :)

Answer 24

so is it d or c?

Answer 25

it would help if you had something useful to contribute to the conversation ... imo

Answer 26

the wording of the ? would assume population and not sample to me

Answer 27

ah i see
http://www.documentingexcellence.com/stat_tool/SD.htm
learn something new every day!
i would assume "population" here, but that is an assumption

Answer 28

This seems to be the the standard deviation of the sample is the same as the population standard deviation so the denominator should be \(n \)

Answer 29

See here: http://en.wikipedia.org/wiki/Standard_deviation#Estimation