csat-suneung 2005 Q20

csat-suneung · South-Korea · csat__math-humanities 3 marks Discrete Probability Distributions Probability Distribution Table Completion and Expectation Calculation
The probability distribution table of random variable $X$ is shown below. Find the variance of random variable $Y = 10 X + 5$. [3 points]
$X$0123Total
$\mathrm { P } ( X )$$\frac { 2 } { 10 }$$\frac { 3 } { 10 }$$\frac { 3 } { 10 }$$\frac { 2 } { 10 }$1
The probability distribution table of random variable $X$ is shown below. Find the variance of random variable $Y = 10 X + 5$. [3 points]

\begin{center}
\begin{tabular}{ | c | c | c | c | c | c | }
\hline
$X$ & 0 & 1 & 2 & 3 & Total \\
\hline
$\mathrm { P } ( X )$ & $\frac { 2 } { 10 }$ & $\frac { 3 } { 10 }$ & $\frac { 3 } { 10 }$ & $\frac { 2 } { 10 }$ & 1 \\
\hline
\end{tabular}
\end{center}