cumulative distribution function
cumulative distribution function — idiom
1. In probability and statistics, for any chosen value x, a cumulative distribution
In probability and statistics, for any chosen value x, a cumulative distribution function gives the probability of a random variable being at or below x. It shows how probability builds from the lowest outcome upward.
To find what share of students scored 70 or lower, the teacher checked the cumulative distribution function at 70.
cumulative distribution function at [value]
Diya plotted the cumulative distribution function of income to show what share of households earn under $40,000 a year.
plotted the cumulative distribution function of [variable]
Valentina computed the battery CDF to find what share of cells fail before 500 cycles.
Marco used the cumulative distribution function to find the median — the point where the function reaches exactly 0.5.
- distribution function
shorter form; refers to the same mathematical object
- probability distribution function
sometimes used interchangeably, though strictly more general
- probability density function
describes the rate of change of the CDF; the two are mathematically related but give different information
- probability mass function
used for discrete random variables instead of continuous ones
用法筆記
Often abbreviated CDF. Frequently paired with 'probability density function' (PDF) as a contrasting concept.