cumulative distribution function
cumulative distribution function — 慣用語
1. In probability and statistics, for any chosen value x, a cumulative distribution
累積分佈函數
變數小於等於某值之機率
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.
為了知道有多少學生考70分或更低，老師查了70分的累積分佈函數值。
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.
Diya 繪製了收入的累積分佈函數圖，以顯示多少家庭年收入低於四萬美元。
plotted the cumulative distribution function of [variable]
Valentina computed the battery CDF to find what share of cells fail before 500 cycles.
Valentina 計算了電池的累積分佈函數，以找出500次循環前故障的電池芯佔多少比例。
Marco used the cumulative distribution function to find the median — the point where the function reaches exactly 0.5.
Marco 用累積分佈函數找出中位數——也就是函數值剛好達到0.5的那個點。
- 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.