trader_var()
计算一组数据的方差
(PECL trader >= 0.2.0)
trader_var — 方差
说明
trader_var(array $real, int $timePeriod = ?, float $nbDev = ?): array
参数
real
浮点数数组。
timePeriod
Number of period. Valid range from 2 to 100000.
nbDev
返回值 ¶
Returns an array with calculated data or false on failure.