Overtime Hours
a Personnel Manager Is Reviewing Number of Overtime

Overtime hours
A personnel manager is reviewing number of overtime hours worked by employees in her plant.She has compiled the following data: $$\begin{array} { | c | c | c | } \hline \begin{array} { c } \text { Number. of Overtime } \\\text { Hours Worked }\end{array} & \begin{array} { c } \text { No. of Employees } \\\text { (Frequency) }\end{array} & \begin{array} { c } \text { Probability } \\\text { P(x) }\end{array} \\\hline 0 & 12 & 0.128 \\3 & 18 & 0.191 \\4 & 10 & 0.106 \\5 & 13 & 0.138 \\6 & 15 & 0.160 \\7 & 12 & 0.128 \\8 & 14 & 0.149 \\\hline \text { Total } & 94 & 1.000 \\\hline\end{array}$$ For a randomly selected employee let X be the number of overtime hours worked,and define the following events:
A = employee who works no overtime.
B = employee who works at least 7 hours overtime.
C = employee who works at most 4 hours overtime.
-Determine the probability of event B.