A company wishes to monitor the variation in the length of time it takes to process and send a bill to a customer. Seven bills will be randomly selected each day for a 60-day period and the length of time it takes to process and send the bill to a customer will be recorded for each bill. The appropriate control chart is a(n):

R - chart

Step-by-step explanation:

Range chart (R chart) is a control chart used for processes with two or more subgroups to determine if a process is stable or not. It monitors the mean and range of a normally distributed variable simultaneously collected at regular intervals during a given time. It is used when measuring small subgroups between two and ten at regular intervals from a process. Iy is a;so used for constant subgroups.