stats_dens_f
(PECL stats >= 1.0.0)
stats_dens_f — Probability density function of the F distribution
说明
   stats_dens_f
    ( float 
  $x
   , float $dfr1
   , float $dfr2
   ) : float
   Returns the probability density at x, where the
   random variable follows the F distribution of which the degree of freedoms
   are dfr1 and dfr2.
  
参数
- 
x
- 
      The value at which the probability density is calculated 
- 
dfr1
- 
      The degree of freedom of the distribution 
- 
dfr2
- 
      The degree of freedom of the distribution 
返回值
   The probability density at x or FALSE for failure.