The cumulative distribution function gives the probability that the r.v. 
is less than or equal to x:
Note that since 
, and the integral of 
is normalized
to unity, 
obeys the following conditions:
is monotone increasing
Figure 5
illustrates a representative cdf.
Note the dependence of 
as
.
Since 
is the indefinite integral of 
, 
.
The cdf can also be
defined for a discrete pdf; however, this will be deferred until we discuss the
subject of sampling from a discrete distribution.
Figure 5: Representative Cumulative Distribution Function (cdf).
