The owner of a local movie theater keeps track of the number of tickets sold in each purchase and makes a probability distribution based on these records. Let [tex]$X$[/tex] represent the number of tickets bought in one purchase. The distribution for [tex]$X$[/tex] is given in the table below.

\begin{tabular}{|c|c|c|c|c|c|}
\hline
Number of Tickets & 1 & 2 & 3 & 4 & 5 \\
\hline
Probability & 0.29 & 0.44 & 0.19 & 0.06 & 0.02 \\
\hline
\end{tabular}

What is the median of the distribution?

A. 2
B. 2.1
C. 2.5
D. 3



Answer :

To determine the median of the given probability distribution, we'll follow these steps:

1. List the tickets and their corresponding probabilities:

[tex]\[ \begin{array}{c|c} \text{Number of Tickets (X)} & \text{Probability} \\ \hline 1 & 0.29 \\ 2 & 0.44 \\ 3 & 0.19 \\ 4 & 0.06 \\ 5 & 0.02 \\ \end{array} \][/tex]

2. Find the cumulative distribution:

Compute the cumulative probabilities by adding the probabilities sequentially:
[tex]\[ \begin{array}{c|c|c} \text{Number of Tickets (X)} & \text{Probability} & \text{Cumulative Probability} \\ \hline 1 & 0.29 & 0.29 \\ 2 & 0.44 & 0.29 + 0.44 = 0.73 \\ 3 & 0.19 & 0.73 + 0.19 = 0.92 \\ 4 & 0.06 & 0.92 + 0.06 = 0.98 \\ 5 & 0.02 & 0.98 + 0.02 = 1.00 \\ \end{array} \][/tex]

This gives us the cumulative distribution:
[tex]\[ [0.29, 0.73, 0.92, 0.98, 1.00] \][/tex]

3. Determine the median:

The median is the point at which the cumulative probability reaches or exceeds 0.5. From the cumulative distribution:
[tex]\[ \begin{array}{c|c} \text{Number of Tickets (X)} & \text{Cumulative Probability} \\ \hline 1 & 0.29 \\ 2 & 0.73 \\ 3 & 0.92 \\ 4 & 0.98 \\ 5 & 1.0 \\ \end{array} \][/tex]
We see that at [tex]\(X = 2\)[/tex], the cumulative probability is 0.73, which is the first value greater than or equal to 0.5.

Therefore, the median of the distribution is 2.