Find the mean and variance of the r.v. X if it has p.m.f. P(X=1)=0.2 , P(X=2)=0.3 and P(X=3) = 0.5 ?

A First Course in Probability (10th Edition)
10th Edition
ISBN:9780134753119
Author:Sheldon Ross
Publisher:Sheldon Ross
Chapter1: Combinatorial Analysis
Section: Chapter Questions
Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...
icon
Related questions
Topic Video
Question

2. Find the mean and variance of the r.v. X if it has p.m.f. P(X=1)=0.2 , P(X=2)=0.3 and P(X=3) = 0.5 ?

3. In a large class, on exam 1, the mean and standard deviation of scores were 78 and 20, respectively, for exam 2, the mean and standard dervationwere 72 and 15, respectively. The covariance of the exam scroes was 80. Give the mean and standard deviation of the sum of the two exam scores. Assume all students took both exams.

Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 2 steps

Blurred answer
Knowledge Booster
Hypothesis Tests and Confidence Intervals for Means
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, probability and related others by exploring similar questions and additional content below.
Recommended textbooks for you
A First Course in Probability (10th Edition)
A First Course in Probability (10th Edition)
Probability
ISBN:
9780134753119
Author:
Sheldon Ross
Publisher:
PEARSON
A First Course in Probability
A First Course in Probability
Probability
ISBN:
9780321794772
Author:
Sheldon Ross
Publisher:
PEARSON