Question

tossing a fair die is an experiment that can result in any integer number from 1 to 6 with equal probabilities .let X be the number of dots face of a die .compute E(x) and var(x)

Answer 1

E(x)=3.5 in your head, since it is the average

Answer 2

\[\frac{1+2+3+4+5+6}{6}=3.5\]

Answer 3

What about when two dice is thrown? :) Not so much in head now :D

Answer 4

ffm can compute the variance, but probably need pencil and paper for this one

Answer 5

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

Answer 6

Pencil + Paper or simply Mathematica ? ;-)

Answer 7

you can do it for two dice in your head too, it is 7, most likely roll

Answer 8

Wow sat! you are amazing :D

Answer 9

How do you did it?

Answer 10

@satellite73 Ping! waiting ...

Answer 11

ok thank u :) now i can computer variance by myself.