
EMPIRICAL CDF PLOTName:
where T is the lifetime of a randomly selected unit. A empirical cdf plot is a plot of the empirical CDF versus failure time. The failure time is plotted on the horizontal axis. At each failure time, the following two points are calculated and plotted on the vertical axis:
\( y_2 = \frac{i}{n} \) with n and i denoting the number of data points and the rank of the failure time, respectively. The last failure time only calculates one of these points. When all of the points are connected, a staircase type plot results. The vertical step is constant for the failure times, while the lengths of the horizontal steps are determined by the distances between failure times. This plot is closely related to the TAIL AREA PLOT and the KAPLAN MEIER PLOT.
where <y> is a response variable containing failure times; and where the <SUBSET/EXCEPT/FOR qualification> is optional.
where <y> is a response variable containing counts; <x> is a response variable containing failure times; and where the <SUBSET/EXCEPT/FOR qualification> is optional.
This synatx is used for binned data. That is,
EMPIRICAL CDF PLOT Y1 SUBSET TAG > 1 EMPIRICAL CDF PLOT Y X
These confidence intervals are based on a binomial approximation to the normal distribution (Higgins, pp. 1516)
with \( \phi \) and \( \alpha \) denoting the percent point function of the standard normal distribution and the confidence level, respectively. By default, 95% confidence levels are generated. To specify a different confidence level, enter the command
where common values for <value> are 0.90 or 0.99.
2023/05: Added support for approximate confidence intervals SKIP 25 READ HAHN.DAT MILES TAG TITLE EMPIRICAL CDF PLOT OF HAHN.DAT XLIMITS 0 150000 Y1LABEL CDF X1LABEL FAILURE TIME EMPIRICAL CDF PLOT MILESProgram 2: . Step 1: Read some data . skip 25 read weibbury.dat y skip 0 . . Step 2: Set some plot control . case asis title case asis tic mark label case asis label case asis . line solid dotted dotted line color black blue blue . ylimits 0 1 . . Step 3: Generate plot . set empirical cdf plot confidence limits on empirical cdf plot y  
Date created: 6/5/2001 Last updated: 05/18/2023 Please email comments on this WWW page to alan.heckert@nist.gov. 