Question
Two numbers are selected at random (without replacement) from first six positive integers. Let X denote the larger of the two numbers obtained. Find the probability distribution of X. Find the mean and variance of this distribution.

Answer

$\text{x}:$ 2 3 4 5 6
$\text{P(x):}$ $\frac{1}{15}$ $\frac{2}{15}$ $\frac{3}{15}$ $\frac{4}{15}$ $\frac{5}{15}$
$\text{x.P(x):}$ $\frac{2}{15}$ $\frac{6}{15}$ $\frac{12}{15}$ $\frac{20}{15}$ $\frac{30}{15}$
$\text{x}^{2}\text{P(x):}$ $\frac{4}{15}$ $\frac{18}{15}$ $\frac{48}{15}$ $\frac{100}{15}$ $\frac{80}{15}$
$\text{Mean} = \sum \text{x. P(x)} = \frac{70}{15}=\frac{14}{3}$
$\text{Variance} = \sum \text{x}^{2}\text{p(x) = (Mean)}^{2} = \frac{350}{15}-\frac{196}{9} = \frac{14}{9} $

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

Evaluate the following intregals:
$\int\frac{\text{x}^2}{\text{x}^4-\text{x}^2-12}\ \text{dx}$
Differentiate the following w.r.t. x:
$\cos^{-1}\Big(\frac{\sin\text{x}+\cos\text{x}}{\sqrt{2}}\Big),\frac{-\pi}{4}<\text{x}<\frac{\pi}{4}$
A small firm manufactures necklaces and bracelets. The total number of necklaces and bracelets that it can handle per day is at most 24. It takes one hour to make a bracelet and half an hour to make a necklace. The maximum number of hours available per day is 16. If the profit on a necklace is Rs. 100 and that on a bracelet is Rs. 300. Formulate on L.P.P. for finding how many of each should be produced daily to maximize the profit?
It is being given that at least one of each must be produced.
Using differentials, find the approximate values of the following:$\frac{1}{\sqrt{25.1}}$
Using elementary transformations, find the inverse of the following matrix:
$\begin{bmatrix} 0 & 1 & 2 \\ 1 & 2 & 3 \\ 3 & 1 & 0 \end{bmatrix} $
Find $\frac{\text{dy}}{\text{dx}}$ in the following cases:
$\sin\text{ xy}+\cos(\text{x}+\text{y})=1$
Show that the height of the cone of maximum volume that can be inscribed in a sphere of radius 12cm is 16cm.
Prove that the given vectors are non-coplanar:
$3\hat{\text{i}}+\hat{\text{j}}-\hat{\text{k}},\ 2\hat{\text{i}}-\hat{\text{j}}+7\hat{\text{k}}$ and $7\hat{\text{i}}-\hat{\text{j}}+23\hat{\text{k}}$
Using differentials, find the approximate values of the following:
$(15)^{\frac{1}{4}}$
Evaluate the following intregals:
$\int\frac{\text{x}^3}{(\text{x}-1)(\text{x}-2)(\text{x}-3)}\ \text{dx}$