Recent questions and answers in Probability & Statistics

Let $\text{X}$ and $\text{Y}$ be two real-valued random variables with $\mathrm{E}(\mathrm{X})=1, \mathrm{E}(\mathrm{Y})=2, \mathrm{E}\left(\mathrm{X}^{2}\right)=4, \math...

Consider discrete random variables $X$ and $Y$ with probabilities as follows:$$ \begin{array}{l} P(X=0 \text { and } Y=0)=\frac{1}{4} \\ P(X=1 \text { and } Y=0)=\frac{1}...

Let $X$ and $Y$ be continuous random variables with probability density functions $P_{X}(x)$ and $P_{Y}(y)$, respectively. Further, let $Y=X^{2}$ and$$P_{X}(x)=\begin{cas...

​​​​​Let $\text{X}$ be a discrete random variable that is uniformly distributed over the set $\{-10,-9, \cdots, 0, \cdots, 9,10\}$. Which of the following random variable...

One million random numbers are generated from a statistically stationary process with a Gaussian distribution with mean zero and standard deviation $\sigma_o$.The $\sigma...

Let the probability density function of a random variable $x$ be given as $$f\left ( x \right ) = ae^{-2\left | x \right |}$$ The value of $’a’$ is _________________.

Two independent random variables $X$ and $Y$ are uniformly distributed in the interval $[-1,1]$. The probability that $\text{max}[X,Y]$ is less than $1/2$ is$3/4$$9/16$$1...

Assume that in traffic junction, the cycle of the traffic signal lights is $2$ minutes of green (Vehicle does not stop) and $3$ minutes of red (Vehicle stops). Consider t...

A continuous random variable $X$ has a probability density function $f(x)=e^{-x}, 0< x< \infty$. then $P\{X 1\}$$0.368$$0.5$$0.632$$1.0$

Lifetime of an electric bulb is a random variable with density $f(x)=kx^2$ , where $x$ is measured in years. If the minimum and maximum lifetimes of bulb are $1$ and $2$ ...

Let $X$ be a random variable with probability density function$f(x)=\begin{cases} 0.2,& \text{for } \mid x \mid \leq 1\\ 0.1,& \text{for }1< \mid x \mid \leq 4\\ 0 & \tex...

A fair coin is tossed $n$ times. The probability that the difference between the number of heads and tails is $(n-3)$ is$2^{-n}$$0$$^{n}C_{n-3}2^{-n}$$2^{-n+3}$

Two coins $R$ and $S$ are tossed. The $4$ joint events $H_{R}H_{S}, T_{R}T_{S}, H_{R}T_{S}, T_{R}H_{S}$ have probabilities $0.28, 0.18, 0.30, 0.24$, respectively, where $...

A random variable $X$ has probability density function $f(x)$ as given below:$ f(x)= \begin{cases} a+bx & \text{ for } 0 < x < 1 \\ 0 & \text{otherwise} \end{cases}$If...

Let the probability density function of a random variable, $X$, be given as:$f_{x}(x)=\frac{3}{2}e^{-3x}u(x)+ae^{4x}u(-x)$where u(x) is the unit step function.Then the va...

Candidates were asked to come to an interview with $3$ pens each. Black, blue, green and red were the permitted pen colours that the candidate could bring. The probabilit...