# MCQs Random Variables 4

1. If $Var(X) = 2$ and $Var(Y) = 5$, and if $X$ and $Y$ are independent variables, then $Var(2X – Y)=$?

2. $E(X-\mu)$ = ?

3. If $Var(X) = 8$ then $Var(X+3)=$

4. If $X$ is a random variable then $E(4X + 2)$ is

5. If $X$ and $Y$ are two independent variables then $E(XY)=$

6. If $X$ is a random variable and $a$ and $b$ are constants, then $SD(a-bX)$ is

7. If $a$ is constant then $Var(a)$ is

8. If $E(X) = 3$ then what will be $E(a+X)$, where $a$ is a constant whose value is 2

9. If $Var(X) = 5$ then $Var(2X + 5)$ =

10. If $E(X) = 1.6$ then $E(5X+10) =$?

11. If $X$ and $Y$ are random variables then $E(X-Y)$ is

12. If $P(X=10) = \frac{1}{10}$, then $E(X)=$?

13. If $X$ and $Y$ are independent random variables then $SD(X-Y)$ will be

A Random Variable (random quantity or stochastic variable) is a set of possible values from a random experiment.

The domain of a random variable is called sample space. For example, in the case of a coin toss experiment, there are only two possible outcomes, namely heads or tails. A random variable can be either discrete or continuous. The discrete random variable takes only certain values such as 1, 2, 3, etc., and a continuous random variable can take any value within a range such as the height of persons.