If a cubical die is thrown,then the mean and variance of the random variable $X$,representing the number on the face that shows up,are respectively:

  • A
    $\frac{2}{7}, \frac{12}{35}$
  • B
    $\frac{7}{2}, \frac{12}{35}$
  • C
    $\frac{1}{7}, \frac{1}{12}$
  • D
    $\frac{7}{2}, \frac{35}{12}$

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Similar Questions

If the mean of the following probability distribution of a random variable $X$ is $\frac{46}{9}$,then the variance of the distribution is:
$X$ $0$ $2$ $4$ $6$ $8$
$P(X)$ $a$ $2a$ $a+b$ $2b$ $3b$

Let a sample space be $S = \{\omega_{1}, \omega_{2}, \ldots, \omega_{6}\}$. Which of the following assignments of probabilities to each outcome is valid?
OutcomeProbability
$\omega_{1}$$\frac{1}{12}$
$\omega_{2}$$\frac{1}{12}$
$\omega_{3}$$\frac{1}{6}$
$\omega_{4}$$\frac{1}{6}$
$\omega_{5}$$\frac{1}{6}$
$\omega_{6}$$\frac{3}{2}$

If $m$ and $\sigma^2$ are the mean and variance of the random variable $X$,whose distribution is given by:
$X=x$$0$$1$$2$$3$
$P(X=x)$$\frac{1}{3}$$\frac{1}{2}$$0$$\frac{1}{6}$

Then:

For the given probability distribution,find $E(X^2)$.
$X$$1$$2$$3$$4$
$P(X)$$\frac{1}{10}$$\frac{1}{5}$$\frac{3}{10}$$\frac{2}{5}$

If the probability density function (p.d.f.) of a continuous random variable $X$ is given by $f(x) = \begin{cases} k(9 + 8x - x^2), & \text{for } -1 \leq x \leq 4 \\ 0, & \text{otherwise} \end{cases}$, then the value of $k$ is:

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