1. Let X be a random variable having pdf f(r) = 6r(1 – 2) for 0 < z < 1 and 0 elsewhere. Compute the mean and variance of X.

Calculus For The Life Sciences
2nd Edition
ISBN:9780321964038
Author:GREENWELL, Raymond N., RITCHEY, Nathan P., Lial, Margaret L.
Publisher:GREENWELL, Raymond N., RITCHEY, Nathan P., Lial, Margaret L.
Chapter1: Functions
Section1.2: The Least Square Line
Problem 8E
icon
Related questions
Question
1. Let X be a random variable having pdf f(x) = 6x(1 – x) for 0 < I < 1 and 0 elsewhere.
Compute the mean and variance of X.
2. Let X1, X2,..., X, be independent random variables having the same distribution as the variable
from problem 1, and let X, = (X1+ ·.+Xn).
Part a: Compute the mean and variance of X, (your answer will depend on n).
Part b: If I didn't assume the variables were independent, would the calculation in part a still
work? Or would at least part of it still work?
3. Suppose that X and Y are both independent variables, and that each has mean 2 and variance
3. Compute the mean and variance of XY (for the variance, you may want to start by computing
E(X²Y²)).
4. Suppose that (X,Y) is a point which is equally likely to be any of {(0, 1), (3,0), (6, 1), (3, 2)}
(meaning, for example, that P(X = 0 and Y = 1) = }).
Part a: Show that E(XY) = E(X)E(Y).
Part b: Are X and Y independent? Explain.
5. Let X be a random variable having a pdf given by
S(2) = 2e-2" for 0 <I< ∞, 0 otherwise .
Part a: Compute the moment generating function of X. For what t is it defined?
Part b: Using your answer to part a, determine E(X), E(X²), and Var(X).
Transcribed Image Text:1. Let X be a random variable having pdf f(x) = 6x(1 – x) for 0 < I < 1 and 0 elsewhere. Compute the mean and variance of X. 2. Let X1, X2,..., X, be independent random variables having the same distribution as the variable from problem 1, and let X, = (X1+ ·.+Xn). Part a: Compute the mean and variance of X, (your answer will depend on n). Part b: If I didn't assume the variables were independent, would the calculation in part a still work? Or would at least part of it still work? 3. Suppose that X and Y are both independent variables, and that each has mean 2 and variance 3. Compute the mean and variance of XY (for the variance, you may want to start by computing E(X²Y²)). 4. Suppose that (X,Y) is a point which is equally likely to be any of {(0, 1), (3,0), (6, 1), (3, 2)} (meaning, for example, that P(X = 0 and Y = 1) = }). Part a: Show that E(XY) = E(X)E(Y). Part b: Are X and Y independent? Explain. 5. Let X be a random variable having a pdf given by S(2) = 2e-2" for 0 <I< ∞, 0 otherwise . Part a: Compute the moment generating function of X. For what t is it defined? Part b: Using your answer to part a, determine E(X), E(X²), and Var(X).
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 2 steps

Blurred answer
Knowledge Booster
Multivariate Distributions and Functions of Random Variables
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, statistics and related others by exploring similar questions and additional content below.
Recommended textbooks for you
Calculus For The Life Sciences
Calculus For The Life Sciences
Calculus
ISBN:
9780321964038
Author:
GREENWELL, Raymond N., RITCHEY, Nathan P., Lial, Margaret L.
Publisher:
Pearson Addison Wesley,
Algebra & Trigonometry with Analytic Geometry
Algebra & Trigonometry with Analytic Geometry
Algebra
ISBN:
9781133382119
Author:
Swokowski
Publisher:
Cengage
Glencoe Algebra 1, Student Edition, 9780079039897…
Glencoe Algebra 1, Student Edition, 9780079039897…
Algebra
ISBN:
9780079039897
Author:
Carter
Publisher:
McGraw Hill