Question

what is the expected value of x^2 in mathematical form?

Answer 1

in a simplified form

Answer 2

what do you mean?

Answer 3

\(x \times x\) I think that's what you mean.

Answer 4

yeah

Answer 5

mathematical form?

Answer 6

Hmm. Similarly:

\( \color{Black}{\Rightarrow x^3 = x \times x\times x}\)
\( \color{Black}{\Rightarrow x^4 = x \times x \times x \times x}\)

Answer 7

'Mathematical form' is still ambiguous.

Answer 8

some stats people know may know

Answer 9

\[\langle x^2\rangle =\sum\limits_{j=0}^\infty x^2 P(j)\]

Answer 10

lol

Answer 11

\[\int 2xdx\]

Answer 12

this reminds me of a very fundamental/basic question in calculus..please see my next question..i'll post link..

Answer 13

\[\frac{d}{dx} (\frac{x^3}{3})\]

Answer 14

what are you doing at @lgbasallote ,

Answer 15

\[x^2 = r^2 - y^2\]

Answer 16

trying to get all that's x^2 and see if anythign suits him

Answer 17

http://openstudy.com/study?login#/updates/4ffffc85e4b0848ddd64e880

Answer 18

im pretty sure i have provided the answer to the question

Answer 19

we all think that...

Answer 20

,oh

Answer 21

i need E(x^2)=?

Answer 22

the expectiation value of \(x\) \[\langle x\rangle =E(x)\]

Answer 23

@UnkleRhaukus yes but x^2

Answer 24

\[Var(x)=E(x^2)-(E(x))^2\]

Answer 25

i got the ans... thanks all

Answer 26

\[\sigma_x=\langle x^2\rangle-\langle x\rangle ^2\]

Answer 27

:D

Answer 28

ya ur right

Answer 29

The expectation value , or expect value of a function
is \[\langle f(x)\rangle =\sum\limits_{x=0}^\infty f(x)P(x)\]
where \(P(x)\) is the probability of x

Answer 30

yes for a discrete random variable

Answer 31

im not sure why i put j instead of x,

Answer 32

oh, you want a continuous function?

Answer 33

no i know

Answer 34

thank you

Answer 35

\[\langle f(x)\rangle=\int\limits_{-\infty}^\infty f(x)\rho(x)\text dx\]

Answer 36

ya

Answer 37

where \(\rho(x)\) is the probability density

Answer 38

so
\[\langle x^2\rangle=\int\limits_{-\infty}^\infty x^2\rho(x)\text dx\]

Answer 39

@UnkleRhaukus small question the E(constant) is a constant right

Answer 40

if the distribution of the variable \(x\) is constant , yes

Answer 41

thanks