Thread: The mean and Variance!

Hello,

I need some help with this maths problem and I would appreciate if I can have a solution a.s.a.p cause I have to hand in my paper today before midnight.

The problem is about the mean and variance. Here it is:"a continuous random variable X is defined for 0< = X < = 2 and has a probability density function given by f(x)=|1-x|. Calculate the mean and variance of this continous random variable"

'<=' - means greater equal than...

THANK YOU VERY MUCH...

Tom

Hello,

Originally Posted by adelante

Hello,

I need some help with this maths problem and I would appreciate if I can have a solution a.s.a.p cause I have to hand in my paper today before midnight.

The problem is about the mean and variance. Here it is:"a continuous random variable X is defined for 0< = X < = 2 and has a probability density function given by f(x)=|1-x|. Calculate the mean and variance of this continous random variable"

'<=' - means greater equal than...

THANK YOU VERY MUCH...

Tom

So the pdf is |1-x| if x is between 0 & 2.


that's a formula you should know...


So
in order to compute this integral, split it into two integrals : one with the domain where 1-x is positive (and hence |1-x|=1-x), one with the domain where 1-x is negative (and hence |1-x|=-(1-x)=x-1)

Same thing :

Hey dude,

Thank you very much again...


Tom

You should use the short cut formula for the variance

and you need to break this integral into two pieces,
from (0,1) and (1,2).

Actually I tried both of them, but thank you for your hint.