csat-suneung 2012 Q6

csat-suneung · South-Korea · csat__math-humanities 3 marks Discrete Probability Distributions Probability Distribution Table Completion and Expectation Calculation
The probability distribution of a random variable $X$ is shown in the table below.
$X$012Total
$\mathrm { P } ( X = x )$$\frac { 1 } { 4 }$$a$$2a$1

What is the value of $\mathrm { E } ( 4X + 10 )$? [3 points]
(1) 11
(2) 12
(3) 13
(4) 14
(5) 15
The probability distribution of a random variable $X$ is shown in the table below.

\begin{center}
\begin{tabular}{ | c | c | c | c | c | }
\hline
$X$ & 0 & 1 & 2 & Total \\
\hline
$\mathrm { P } ( X = x )$ & $\frac { 1 } { 4 }$ & $a$ & $2a$ & 1 \\
\hline
\end{tabular}
\end{center}

What is the value of $\mathrm { E } ( 4X + 10 )$? [3 points]\\
(1) 11\\
(2) 12\\
(3) 13\\
(4) 14\\
(5) 15