<s>[INST] How to get the expected value of these numbers? 
So for the E(x) of (a)  I got 1 $\cdot$ ($\frac{1}{5} $) + 3 $\cdot$ ($\frac{2}{5} $)+ 9 $\cdot$ ($\frac{2}{5} $) = 9.8
Why is the answer showing E(x)= 5? 
Also To compute the Variance, according to the formula, E($X^2$) - E$(X)^2$ shouldn't the answer be $\frac{181}{5} $ - $\frac{625}{5}$ ?
Many thanks in advance !
 [/INST] 
So for the E(x) of (a) I got $1 \cdot \tfrac 15 + 3 \cdot \tfrac25+ 9 \cdot\tfrac25 = 9.8$
Why is the answer showing E(x)= 5?

Because $\tfrac {1+ 6+18}5 =\tfrac {25}5$  not $\tfrac {49}5$ (...how did you even?)

Also To compute the Variance, according to the formula, E($X^2$) - E$(X)^2$ shouldn't the answer be $\frac{181}{5} $ - $\frac{625}{5}$ ?

$$\dfrac{1+2\cdot 3^2+2\cdot 9^2}{5}-\left(5\right)^2=\dfrac{181}5-\dfrac {125}5=\dfrac{56}5$$
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