Diagnostic daytime multiple sleep latency test (MSLT) is used to diagnose narcolepsy and to measure the degree of daytime sleepiness. It measures how quickly you fall asleep in quiet situations during the day. It also monitors how quickly and how often you enter REM sleep.
Array formulas provide a way by which Excel users can discover such useful information. To explain the power of array formulas I'll use this database. It shows sales by Seller, Product, Region, and Customer, with Quantity and Total Sales, in dollars. I named each column of data with the label shown in row 1.
Array constants cannot contain additional arrays, formulas, or functions. In other words, they can contain only text or numbers that are separated by commas or semicolons. Excel displays a warning message when you enter a formula such as {1,2,A1:D4} or {1,2,SUM(Q2:Z8)}.