                                                         

               ADDITIONS AND CHANGES TO THE PROGRAMS
               

The PEPI package has undergone constant revision since the public
issue in 1993 (Gahlinger and Abramson 1993) of Version 1, some of
whose 38 programs had originally been written for programmable
calculators (Abramson and Peritz 1983).  Version 2 added four new
programs (ADJUSTP, RANDOM, RANKCORR and WHATS) and a number of other
changes, which were listed in the manual for Version 2 (Gahlinger and
Abramson 1995).  Numerous additional changes were made in Versions
2.01 to 2.06, which were issued in 1996, but no programs were added.
The main changes in Versions 2.07 and 2.07a, issued in 1997, were a
number of features to enhance user-friendliness, two new programs
(LOGISTIK and LOGX), and the incorporation of one program (POOLING)
into another (COMBINE).  Two more new programs (FREQ and POISSREG)
make their first public appearance in Version 3, and CURVE has been
incorporated into PAIRS.

A major improvement is that all the programs have been modified to
permit problem-free operation even on a Pentium II computer operating
at a very fast speed.*   Previous versions produced a "run-time error"
message when used on such a computer, because of a bug in Turbo Pascal
7.0 (the language in which the PEPI programs are written).

PEPI: UPDATE (Version 3.0)
 
                        ADDITIONS AND CHANGES
  
Previous users of the PEPI programs may be interested in the following
list of the main additions and changes since Version 2 was issued in
1995.  Changes first made in Version 3.0 (i.e., since Version 2.07A)
are marked with an asterisk *.

In addition to the additions and changes listed, a major improvement
is that the programs have been modified to permit problem-free
operation even on a high-speed Pentium II computer.*  A number of
features to enhance user-friendliness were added, including Program
Finders for Windows and DOS.


NEW PROGRAMS
 
  FREQ* - Appraisal of a frequency distribution
  LOGISTIK and LOGX - Multiple logistic regression analysis)
  POISSREG* - Poisson regression analysis
   

ADDITIONS AND CHANGES TO SPECIFIC PROGRAMS
                                        
- ADJUSTP  

     Added feature: Finner's method of adjusting P values.*

- CASECONT 

     Added features: DerSimonian-Laird procedure for computing an
     overall odds ratio for a set of studies or strata (random-effects
     model); exact power of Fisher and mid-P exact binomial tests;
     faster computation of exact probabilities and confidence
     intervals.  
     
- CHISQ 

     Added features: Shannon index of diversity;* test for difference
     in diversity between two samples.*

- COMBINE

     Added features: DerSimonian-Laird procedure for computing an
     overall measure of association for a set of studies or strata
     (random-effects model); computation and combination of effect
     sizes (standardized differences between means); can accept
     confidence intervals (instead of standard errors) for the
     measures to be combined.
     
- CONFINT

     Added features: confidence level for values above/below a
     specific point;*  faster computation; accuracy enhanced by use of
     improved function for estimating F from a P value.
   
- DIFFER 

     Added features: Bartlett's test for comparing two variances;*
     confidence intervals for the variance ratio;*  Welch's
     modification to formula for degrees of freedom for t test
     comparing populations with different variances;* estimation of
     effect of regression to the mean.
     
- EXACT2XK

     Added feature: faster computation.

- FIT

     Added features: mean square successive difference test for
     randomness;* Ghent's test for a centrifugal pattern.*
     
- FITTING

     Added feature: tests of variance (as well as chi-square
     goodness-of fit tests) for appraising fit with Poisson and
     binomial distributions.*

- KAPPA 

     Added features: maximum attainable kappa (given the marginal
     totals);* kappa values that compensate for the effects of bias
     and unequal prevalences of categories; kappa for stratified data,
     appropriate for small samples.

- MANNWHIT

     Added features: Cramer-Von Mises test for the difference between
     distributions;* accuracy of Mann-Whitney test improved by use of
     a modified normal approximation procedure.*   
     
- MANTELX

     Added features: heterogeneity test and cumulative odds ratio
     added to the extended Mantel-Haenszel procedure.

- MATCHED

     Added features: estimates conditional power of Walter's test for
     binary data (comparing cases with multiple matched controls);
     faster computation of exact probabilities and confidence
     intervals.  
                                                                     
- PAIRS

     Added features: risk ratio and its confidence intervals;*
     measure of agreement between numerical values and a 'gold
     standard';* comparison of paired numerical values assuming a
     lognormal distribution;* alternative regression curves, and
     projections based on the curves;* faster computation of exact
     probabilities and confidence intervals; accuracy enhanced by use
     of improved function for estimating F from a P value.
     
- POWR

     Added features: power of a test for comparing two independent
     proportions without as well as with a continuity correction;*
     power of Mantel-Haenszel test with as well as without a
     continuity correction;* formula for the power of a paired t test
     was changed.*
     
- PVALUE

     Accuracy enhanced by use of improved function for estimating F
     from a P value.

- RANDOM

     Added feature: a procedure for use in minimalization (balanced
     randomization of trial subjects, so as to minimize differences in
     prognostic factors between the experimental groups).*
     
- RATES1                           

     Added features: confidence intervals for "number needed to
     treat";* DerSimonian-Laird procedure for computing an overall
     rate ratio and rate difference for a set of studies or strata
     (random-effects model).
    
- RATES2
     
     Added features: confidence intervals for "number needed to
     treat";* DerSimonian-Laird procedure for computing an overall
     rate ratio and rate difference for a set of studies or strata
     (random-effects model); faster computation of exact probabilities
     and confidence intervals.

- RELATED 

     Added feature: extended use of tabulated critical values for
     Friedman's two-way analysis of variance by ranks.*
     
- SAMPLE

     Modified formula for sample size for a cluster sample, using the
     finite population correction.*

- SAMPLES 

     Added features: prediction of precision (width of the confidence
     interval that may be expected for a given power);* calculates the
     sample sizes and power required to provide a confidence interval
     of a specified width;* sample sizes for comparisons of ordered
     categories in matched samples;* computation of sample sizes for
     comparing two independent proportions without as well as with a
     continuity correction.*

- SCRN

     Added features: for a screening or diagnostic test that provides
     a range of values, displays a ROC curve showing the association
     between sensitivity and the false positive rate, computes the
     area under the curve, and determines the optimal cut-points under
     different conditions.

- SEASONAL 

     Added feature: Hewitt's rank-sum test for seasonality.

- SMOOTH  

     Added features: kernel smoothing (for rates, risks, proportions
     and other ratios);* modified forecasts from exponentially
     weighted moving averaages.*
     
- TREND 

     Added features: Tukey test for multiple comparisons of means;*
     Dunnett tests for multiple comparisons of proportions and means
     (comparisons with a selected control value).*  Changed formula
     for multiple-comparison tests for proportions.*  
     
- WHATS 
                                                    
     Added features: permutations and combinations; extended factorial
     function.                                                  
     
____________________________

*  Change made in Version 3.
