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Distribution of a linear transformation of a discrete random variable

Question 1 of 8

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A discrete model assigns an integer cost to each outcome

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

\(x\)\(\Pr(X=x)\)
\(3\)\(\frac{1}{7}\)
\(4\)\(\frac{4}{7}\)
\(6\)\(\frac{2}{7}\)

Define \(Y\) by the rule

\[Y = 2\,X + 3.\]
(a)3 marks

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

\(y\)\(\Pr(Y=y)\)
\(\square\)\(\frac{1}{7}\)
\(11\)\(\square\)
\(\square\)\(\frac{2}{7}\)
(b)1 mark

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

(c)1 mark

Find the expected value of \(Y\)

Format: exact fraction