g01aef

Purpose

Synopsis

[cint,ifreq,xmin,xmax,ifail] = g01aef(x,iclass,cint<,ifail>)

Description

 
 The data consists of a sample of n observations of a continuous 
 variable, denoted by x , for i=1,2,...,n. Let a=min(x ,...,x ) 
                       i                              1      n 
 and b=max(x ,...,x ).
            1      n 
 
 The routine constructs a frequency distribution with k(>1) 
 classes denoted by f , for i=1,2,...,k.
                     i                 
 
 The boundary values may be either user-supplied, or routine-
 calculated, and are denoted by y , for j=1,2,...,k-1.
                                 j                   
 
 If the boundary values of the classes are to be routine-
 calculated, then they are determined in one of the following 
 ways:
 
 (a)   If k>2, the range of x values is divided into k-2 intervals
       of equal length, and two extreme intervals, defined by the 
       class boundary values y ,y ,...,y   .
                              1  2      k-1
 
                   1     
 (b)   If k=2, y = -(a+b).
                1  2     
 
 However formed, the values y ,...,y    are assumed to be in 
                             1      k-1                     
 ascending order. The class frequencies are formed with
 
      f  = the number of x values in the interval (-infty,y )
       1                                                   1
 
      f  = the number of x values in the interval [y   ,y ), 
       i                                            k-1  k  
      i=2,....,k-1
 
      f  = the number of x values in the interval [y   ,infty),
       k                                            k-1       
 
 where [ means inclusive, and ) means exclusive. If the class 
 boundary values are routine-calculated and k>2, then f =f =0, and
                                                       1  k    
 y  and y    are chosen so that y <a and y   >b.
  1      k-1                     1        k-1  
 
 If a frequency distribution is required for a discrete variable, 
 then it is suggested that the user supplies the class boundary 
 values; routine-calculated boundary values may be slightly 
 imprecise (due to the adjustment of y  and y    outlined above) 
                                      1      k-1                
 and cause values very close to a class boundary to be assigned to
 the wrong class.
 

Parameters

g01aef

Required Input Arguments:

x (:)                                 real
iclass                                integer
cint (:)                              real

Optional Input Arguments:                       <Default>

ifail                                 integer  -1

Output Arguments:

cint (:)                              real
ifreq (:)                             integer
xmin                                  real
xmax                                  real
ifail                                 integer