Consider a project that is only budgeting for labor. Your project was planned to take $20$ hours of work per week for $3$ months $(12$ weeks$)$ at a pay rate of $$40/$hour$.$ However, during your check$-$in in week $4,$ you learn that your staff received the materials late and have only been able to work for $3$ of the $4$ weeks you$$ve paid for. The good news is they don$$t think they$$ll need any extra time.

a$)$ Explain what type$($s$)$ of cost variance have occurred.

b$)$ What cost management method could the project manager have used to be sure this extra cost could be handled?