A probability distribution with most of its probability near the two limits and least at the center, mathematically the arcsine distribution. It describes a quantity that varies sinusoidally between bounds, such as lab temperature cycling under a controller or RF mismatch error, which spends most of its time near the extremes. For a half-width a, the standard uncertainty is a divided by the square root of 2, about 0.707a.
Lab temp swings plus or minus 1 degree on the HVAC cycle, model it U-shaped, divisor root two.
RF metrologists reach for it every day for mismatch; dimensional labs reach for it when the air handler cycles.
Also heard as
- arcsine distribution
- U-shaped
Related terms
Rectangular distribution
A distribution giving equal likelihood to every value between two limits, used when only the bounds are known.
Triangular distribution
A distribution peaked at the center and falling linearly to zero at the limits, with a divisor of root six.
Probability density function, the curve describing how likely each possible value of a quantity is.
Influence quantity
A condition that is not the thing being measured but still changes the reading, such as temperature or humidity.