\begin{tabular}{|r|r|}
\hline Probability & Scores \\
\hline 0.12 & 0 \\
\hline 0.13 & 1 \\
\hline 0.06 & 2 \\
\hline 0.13 & 3 \\
\hline 0.22 & 9 \\
\hline 0.34 & 11 \\
\hline
\end{tabular}

Find the expected value of the above random variable.

Hint: The expected value of a random variable is the sum of the products of each outcome times its probability.

[tex]$\square$[/tex]



Answer :

To find the expected value of the given random variable, we will apply the formula for the expected value (or mean) of a discrete random variable. The expected value [tex]\( E(X) \)[/tex] is calculated as follows:

[tex]\[ E(X) = \sum_{i} (p_i \times x_i) \][/tex]

where [tex]\( p_i \)[/tex] is the probability of the [tex]\(i\)[/tex]-th outcome and [tex]\( x_i \)[/tex] is the value of that outcome.

Let's break down the calculations step by step using the provided probabilities and scores:

1. Identify the probabilities and corresponding scores:
[tex]\[ \begin{aligned} &p_1 = 0.12, && x_1 = 0, \\ &p_2 = 0.13, && x_2 = 1, \\ &p_3 = 0.06, && x_3 = 2, \\ &p_4 = 0.13, && x_4 = 3, \\ &p_5 = 0.22, && x_5 = 9, \\ &p_6 = 0.34, && x_6 = 11. \end{aligned} \][/tex]

2. Calculate the products of each [tex]\( p_i \)[/tex] and [tex]\( x_i \)[/tex]:
[tex]\[ \begin{aligned} &p_1 \times x_1 = 0.12 \times 0 = 0, \\ &p_2 \times x_2 = 0.13 \times 1 = 0.13, \\ &p_3 \times x_3 = 0.06 \times 2 = 0.12, \\ &p_4 \times x_4 = 0.13 \times 3 = 0.39, \\ &p_5 \times x_5 = 0.22 \times 9 = 1.98, \\ &p_6 \times x_6 = 0.34 \times 11 = 3.74. \end{aligned} \][/tex]

3. Sum these products to find the expected value:
[tex]\[ E(X) = 0 + 0.13 + 0.12 + 0.39 + 1.98 + 3.74 = 6.36. \][/tex]

Therefore, the expected value of the random variable is [tex]\( 6.36 \)[/tex].