 # Explore Random Variables: Examples & Equations

Recent questions in Random variables
College StatisticsOpen question Eisregiony1 2022-08-18

## A population of values has a normal distribution with $\mu =67.9$ and $\sigma =44.8$. You intend to draw a random sample of size n=17.Find the probability that a single randomly selected value is greater than 94

College StatisticsOpen question Nashorn0o 2022-08-18

## Find the following probabilities for a standard normal random variable z : P(-1 <= z<= 1)

College StatisticsOpen question Cecilia Tapia 2022-08-18

## Find the following probabilities for a standard normal random variable z : P(z> 1)

College StatisticsOpen question nascarchic839e9 2022-08-17

## A population is normally distributed with $\mu =100$ and $\sigma =25$.Find the probability that a value randomly selected from this population will have a value greater than 135.

College StatisticsOpen question Erin Larsen 2022-08-17

## Let X and Y be continuous random variables with joint density function$f\left(x,y\right)=\left\{\begin{array}{ll}\frac{x}{5}+cy& 0where c is a constant. Are X and Y independent?

College StatisticsOpen question autumnunfound91 2022-08-17

## The time (in hours) required to repair a machine is an exponentially distributed random variable with parameter $\lambda =1$. What is the conditional probability that a repair takes at least 3 hours, given that its duration exceeds 2 hours? Capriconian321 2022-08-08

## A random variable follow a normal distribution with mean 12 and variance 2.5. Find upper quartile Pooja Singh2022-08-05

## Suppose the cumulative distribution of random variable X is F(x) 0 x< 0 0.2 x 0 <= x < 5 1 5 <=x Determine the following: (a) P (X < 2.8) (b) P (X > 1.5) (c) P (X < -2) (d) P (X > 6) Markus Petty 2022-07-20

## Suppose ${X}_{1},\dots ,{X}_{m}$ and ${Y}_{1},\dots ,{Y}_{n}$ are random variables with the property that $Cov\left({X}_{i},{Y}_{j}\right)<\mathrm{\infty }$ for all i and j. Show that, for any constants ${a}_{1},\dots ,{a}_{m}$ and ${b}_{1},\dots ,{b}_{n}$,$Cov\left(\sum _{i=1}^{m}{a}_{i}{X}_{i},\sum _{j=1}^{n}{b}_{j}{Y}_{j}\right)=\sum _{i=1}^{m}\sum _{j=1}^{n}{a}_{i}{b}_{j}Cov\left({X}_{i},{Y}_{j}\right)$ jayeshmahadik6879 2022-07-19

## when normal distribution curve is more flatter in the case on Tamia Edwards2022-07-07

## The GPA of Students at the University has a normal distributed with a mean of 3.62 and a variance of 6.25. a. Calculate the probability that for a randomly select student, the GPA will be more than 3.99. Shreya Khamrai2022-07-03

## What is the probability that there will be strictly more heads than tails out of 10 flipsof a fair coin? Out of 20 flips?

College StatisticsOpen question Aamyia Bullock2022-06-29

## A restaurant offers a​ \$12 dinner special that has4choices for an​ appetizer,11choices for an​ entrée, and3choices for a dessert. How many different meals are available when you select an​ appetizer, an​ entrée, and a​ dessert?

College StatisticsOpen question Bessy Kinya2022-06-22

##  Eslam Tail2022-06-16

## Toss 3 coin and 2 die find the probability of appearing 3 heads and sum of a dot = 12

College StatisticsOpen question Arpit raj2022-05-25

##  Harrison Kikuyu2022-05-08

## Jane chooses a number X at random from the set of numbers{1, 2, 3, 4}, so thatP(X = k) =14for k = 1, 2, 3, 4.She then chooses a number Y at random from the subset ofnumbers {X, ...,4}; for example, ifX = 3, then Y is chosen atrandom from {3,4}.(i) Find the joint probability distribution of X and Y and displayit in the form of a two-way table.[5 marks](ii) Find the marginal probability distribution of Y , and hencefind E(Y ) and V ar(Y ).[4 marks](iii) Show that Cov(X, Y ) = 5/8.[4 marks](iv) Find the probability distribution of U = X + Y . [7

College StatisticsOpen question

## Consider a sample with data values of 10, 20, 12, 17 and 16. Compute the z-score for the first three observations

College StatisticsOpen question