Search

1 of 8 0-day streak

Distribution of a linear transformation of a discrete random variable

Question 1 of 8

No calculator

A discrete model assigns an integer payoff to each outcome

Let \(X\) be the discrete random variable with the following distribution

\(x\)\(\Pr(X=x)\)
\(-1\)\(\frac{2}{5}\)
\(1\)\(\frac{1}{5}\)
\(4\)\(\frac{1}{10}\)
\(6\)\(\frac{3}{10}\)

Define \(Y\) by the rule

\[Y = 2\,X + 1.\]
(a)4 marks

Complete the table for the distribution of \(Y\)

\(y\)\(\Pr(Y=y)\)
\(\square\)\(\square\)
\(3\)\(\frac{1}{5}\)
\(\square\)\(\frac{1}{10}\)
\(\square\)\(\frac{3}{10}\)
(b)1 mark

Which formula gives the expected value of \(Y\) from the corresponding quantity for \(X\)?

(c)1 mark

Calculate \(E(Y)\)