can anybody solve this.

Printable View

- Apr 29th 2009, 10:50 AMarslanfinding the standard deviation of a radom variable??
can anybody solve this.

- Apr 29th 2009, 10:55 AMMoo
Compute $\displaystyle \mathbb{E}(X)=\sum_{i=1}^3 x_i \mathbb{P}(X=x_i)=0.2 \times 10+0.3\times 20+0.5\times 30$

Complete the table with the values of x^2

Then compute $\displaystyle \mathbb{E}(X^2)=\sum_{i=1}^3 x_i^2 \mathbb{P}(X=x_i)$

The variance is $\displaystyle \mathbb{E}(X^2)-[\mathbb{E}(X)]^2$

That's all folks - Apr 29th 2009, 11:08 AMarslan
- Apr 29th 2009, 04:40 PMmr fantastic