These data will be used to construct a p control chart. The subgroup size is n = 100. The p values for each subgroup (day) have been calculated and are shown in the table. For example, for day 1, there were 22 defective items (np) found in the 100 invoices inspected. Thus, p = np/n = 22/100 = 0.22 or 22%. The p values for the other days are calculated similarly