If a variable takes values 0, 1, 2, ..., n wi | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(B) The total frequency $N = \sum_{r=0}^n {^nC_r} = 2^n$. The sum of the products of values and frequencies is $\sum_{r=0}^n r \cdot {^nC_r} = 0 \cdot

Vedclass · Accepted Answer

$\frac{n}{2}$

Vedclass · Answer

(B) The total frequency $N = \sum_{r=0}^n {^nC_r} = 2^n$. The sum of the products of values and frequencies is $\sum_{r=0}^n r \cdot {^nC_r} = 0 \cdot {^nC_0} + 1 \cdot {^nC_1} + 2 \cdot {^nC_2} + ... + n \cdot {^nC_n}$. Using the identity $r \cdot {^nC_r} = n \cdot {^{n-1}C_{r-1}}$,the sum becomes $\sum_{r=1}^n n \cdot {^{n-1}C_{r-1}} = n \sum_{k=0}^{n-1} {^{n-1}C_k} = n \cdot 2^{n-1}$. Thus,the mean $\bar{x} = \frac{\sum f_i x_i}{N} = \frac{n \cdot 2^{n-1}}{2^n} = \frac{n}{2}$.

Number of smart phones $(x)$	$0$	$1$	$2$	$3$	$4$	$5$
Probability $(P(x))$	$k$	$0.3$	$0.15$	$0.15$	$0.1$	$2k$

$X$	$0$	$1$	$2$	$3$	$4$	$5$	$6$	$7$
$P(X)$	$0$	$k$	$2k$	$3k$	$3k^2$	$k^2$	$2k^2$	$7k^2+k$

If a variable takes values $0, 1, 2, ..., n$ with frequencies proportional to the binomial coefficients $^nC_0, ^nC_1, ..., ^nC_n$,find the mean of the distribution.

Similar Questions

If a discrete random variable $X$ takes the values $1, 2, 3, 4$ such that $2P(X = 1) = 3P(X = 2) = P(X = 3) = 5P(X = 4)$, then $P(X = 4) = ...$ (in $61$)

If $X$ is a Poisson variate such that $\alpha = P(X=1) = P(X=2)$, then $P(X=4)$ is equal to

The following table shows the probability distribution of smart phones sold in a shop per day:
Number of smart phones $(x)$ $0$ $1$ $2$ $3$ $4$ $5$
Probability $(P(x))$ $k$ $0.3$ $0.15$ $0.15$ $0.1$ $2k$

Then $E(x) = ?$

The variance of the following probability distribution is:
$x$ $0$ $1$ $2$
$P(X)$ $\frac{9}{16}$ $\frac{3}{8}$ $\frac{1}{16}$

$A$ random variable $X$ has the following probability distribution:

$X$ $0$ $1$ $2$ $3$ $4$ $5$ $6$ $7$

$P(X)$ $0$ $k$ $2k$ $3k$ $3k^2$ $k^2$ $2k^2$ $7k^2+k$

Determine $P(0 < X < 3)$. (in $/10$)

Vedclass Test Series

Exam Paper Generator

Online Exam Module