A nationwide parcel delivery service keeps track of the number of late deliveries (more than 30 minutes past the time promised to clients) per day. They plan on using a control chart to plot their results

Which type of control chart(s) would you recommend?
A) both x-bar chart and R-chart
B) p-chart
C) c-chart
D) x-bar chart
E) both p-chart and c-chart

C