Solution Found!
Suppose that in Exercise 2.4-1, X = 1 if a red ball is
Chapter 2, Problem 2E(choose chapter or problem)
Problem 2E
Suppose that in Exercise 2.4-1, X = 1 if a red ball is drawn and X = −1 if a white ball is drawn. Give the pmf, mean, and variance of X.
References Exercise 2.4-1
An urn contains 7 red and 11 white balls. Draw one ball at random from the urn. Let X = 1 if a red ball is drawn, and let X = 0 if a white ball is drawn. Give the pmf, mean, and variance of X.
Questions & Answers
QUESTION:
Problem 2E
Suppose that in Exercise 2.4-1, X = 1 if a red ball is drawn and X = −1 if a white ball is drawn. Give the pmf, mean, and variance of X.
References Exercise 2.4-1
An urn contains 7 red and 11 white balls. Draw one ball at random from the urn. Let X = 1 if a red ball is drawn, and let X = 0 if a white ball is drawn. Give the pmf, mean, and variance of X.
ANSWER:
Answer :
Step 1 of 1:
From the given information an urn contains 7 red and 11 white balls.
The total balls is 7+11 = 18 balls.
X=1 IF red ball is drawn.
So P(X=1) =
x=-1 if white ball is drawn.
So P(x=-1) =
Then the pmf is
mean :
Now we need to find the mean.
We know that