A manager records the number of hours, [tex]\(X\)[/tex], each employee works on his or her shift and develops the probability distribution below. Fifty people work for the manager. How many people work 4 hours per shift?

[tex]\[
\begin{array}{|c|c|}
\hline \multicolumn{2}{|c|}{\text{Probability Distribution}} \\
\hline
\begin{array}{r}
\text{Hours} \\
\text{Worked: } X
\end{array} & \text{Probability: } P(X) \\
\hline 3 & 0.1 \\
\hline 4 & ? \\
\hline 5 & 0.14 \\
\hline 6 & 0.3 \\
\hline 7 & 0.36 \\
\hline 8 & 0.06 \\
\hline
\end{array}
\][/tex]



Answer :

To determine how many people work 4 hours per shift, let's first find the probability of an employee working exactly 4 hours (denoted [tex]\( P(X = 4) \)[/tex]) given the provided probability distribution.

Here's the given distribution:
[tex]\[ \begin{array}{|c|c|} \hline \text{Hours Worked} & \text{Probability} \\ \hline 3 & 0.1 \\ \hline 4 & ? \\ \hline 5 & 0.14 \\ \hline 6 & 0.3 \\ \hline 7 & 0.36 \\ \hline 8 & 0.06 \\ \hline \end{array} \][/tex]

We know that the sum of probabilities for all possible values of [tex]\( X \)[/tex] must equal 1. Therefore, we can write the following equation:

[tex]\[ P(X = 3) + P(X = 4) + P(X = 5) + P(X = 6) + P(X = 7) + P(X = 8) = 1 \][/tex]

Plugging in the given probabilities:

[tex]\[ 0.1 + P(X = 4) + 0.14 + 0.3 + 0.36 + 0.06 = 1 \][/tex]

Summing the known probabilities:

[tex]\[ 0.1 + 0.14 + 0.3 + 0.36 + 0.06 = 0.96 \][/tex]

We can now solve for [tex]\( P(X = 4) \)[/tex]:

[tex]\[ P(X = 4) = 1 - 0.96 = 0.04 \][/tex]

This means that the probability of an employee working exactly 4 hours is 0.04.

Now, we need to find out how many out of the 50 employees work 4 hours per shift. We can do this by multiplying the total number of employees by the probability of working 4 hours:

[tex]\[ \text{Number of people working 4 hours} = 50 \times 0.04 = 2 \][/tex]

Therefore, the number of people who work exactly 4 hours per shift is 2.