STDEV.S
Measure variability.
Why planners need it
How noisy is your volume or AHT? Standard deviation drives buffer staffing and tells you whether a "bad day" is normal noise or a real signal.
Syntax
=STDEV.S(range)
Worked example
Daily volume mean 1,000 with =STDEV.S(Vol) = 120 means most days fall roughly 880–1,120 (mean ± 1 SD).
Coefficient of variation: =STDEV.S(Vol)/AVERAGE(Vol) compares volatility across queues.
Watch out: STDEV.S is for a sample (your history); STDEV.P is for a whole population. For forecasting from samples, use .S.