Many retail stores, such as grocery stores and discount stores, experience long lines during peak periods of the day. the problem is noticeably worse on certain days of the week, such as weekends and before holidays, or when there are sales promotions. there are usually enough workers on the job to open all cash registers. the problem is knowing when to call some of the workers who are performing other activities, such as stocking shelves or customers in the store itself, to the front to work the checkout counters. what type of data would be needed to facilitate good decisions here?