Question

The following table shows the probability distribution for a discrete random variable.

X 13 16 18 21 23 25 26 31
P(X) 0.07 0.21 0.17 0.25 0.05 0.04 0.13 0.08
The mean of the discrete random variable X is 20.59. What is the variance of X? Round your answer to the nearest hundredth.

Answer 1

http://math.elon.edu/statistics112/prob_dist.html

Answer 2

\[s2 = Σ ( x _{I} - x )2 / ( n - 1 )\]

Answer 3

are you there??

Answer 4

yes

Answer 5

can you explain the equation a bit?

Answer 6

sure lets star with \[\sum_{i=1}^{n}\]

Answer 7

do you understand what this means?

Answer 8

yes

Answer 9

good then\[x_{i} -x\] xi is each value of your x value .

-x really i cant use xbar because the keyboard is limited .. x bar is the average= \[xbar=\sum_{i=1} x _{i}/n\]

Answer 10

we are assuming that you have sample and not population as well !!!!

Answer 11

alright..I'm a little lost now

Answer 12

tell me where.

Answer 13

at the last part you posted

Answer 14

"we are assuming that you have sample and not population as well"

that

Answer 15

yes and before that

Answer 16

look. inorder to help you you need to be clear as to where are you not understanding . so i can help you better. thanks

Answer 17

I'm sorry, I just don't understand it.

Answer 18

no need to be sorry . :)

Answer 19

have you done statistics before ?

Answer 20

no, but this is in my algebra 2 work

Answer 21

thats cool/

Answer 22

do you now how to get the mean?

Answer 23

yes

Answer 24

ok so were half way.

Answer 25

lets talk concept first. is that ok?

Answer 26

sure

Answer 27

variance is the distance from the mean measured in squares.