These macros compute nonparametric survival curve estimates from interval-censored data. Confidence intervals for survival curves and log-rank tests comparing survival curves from several groups are also provided.
NOTE: Beginning with SAS/STAT 13.1 in SAS 9.4 TS1M1, the functionality of these macros has been updated and added to the ICLIFETEST procedure. For details, see the ICLIFETEST documentation.
PURPOSE:
These macros compute nonparametric maximum likelihood estimates (NPMLEs) of survival curves from interval-censored data. Confidence intervals for survival curves and log-rank tests comparing survival curves from several groups are also provided.
The %ITEM macro computes descriptive statistics for analysis of data from a multiple-choice test. Each observation contains the answers from one subject to a set of questions ("items"). The data are compared to an answer key to determine which answers are correct. The score for each subject is computed as the number of correct answers. The output is very similar to that from the ITEM procedure in the SUGI Supplemental library, but several incorrect statistics have been fixed.
The %JACK and %BOOT macros do jackknife and bootstrap analyses for simple random samples, computing approximate standard errors, bias-corrected estimates, and confidence intervals assuming a normal sampling distribution.
The %JACK macro does jackknife analyses for simple random samples, computing approximate standard errors, bias-corrected estimates, and confidence intervals assuming a normal sampling distribution.
The %BOOT macro does elementary nonparametric bootstrap analyses for simple random samples, computing approximate standard errors, bias-corrected estimates, and confidence intervals assuming a normal sampling distribution. Also, for regression models, the %BOOT macro can resample either observations or residuals.
The %BOOTCI macro computes several varieties of confidence intervals that are suitable for sampling distributions that are not normal.
The %MULTNORM macro provides tests and plots of multivariate normality. A test of univariate normality is also given for each of the variables. A chi-square quantile-quantile plot of the observations' squared Mahalanobis distances can be obtained allowing a visual assessment of multivariate normality. Univariate histograms with overlaid normal curves are also available.
NOTE: Beginning in SAS 9, you can use the ODS GRAPHICS ON; statement and the PLOTS=SCATTER(ELLIPSE=MEAN) or PLOTS=SCATTER(ELLIPSE=PREDICTED) option in the PROC CORR statement to get confidence ellipse plots about the mean or individual values.
PURPOSE:
The %CONELIP macro generates confidence ellipses for bivariate normal data. It can either create ellipses for the data or ellipses about the mean.
NOTE: The MVN macro is obsolete. Beginning in SAS 9.2, use the RANDNORMAL function in SAS/IML software or PROC SIMNORMAL in SAS/STAT software to generate multivariate normal data.
PURPOSE:
The %MVN macro generates multivariate normal data using the Cholesky root of the variance-covariance matrix. Bivariate normal data can be generated using the DATA step.
NOTE: Beginning in SAS 9.4, this macro is no longer needed. Use the OUTPLC= option in Base SAS PROC CORR to save a matrix of polychoric (or tetrachoric) correlations.
PURPOSE:
The %POLYCHOR macro creates a SAS data set containing a correlation matrix of polychoric correlations or a distance matrix based on polychoric correlations.
Nonparametric comparison of areas under correlated ROC curves. Provides point and confidence interval estimates of each curve's area and of the pairwise differences among the areas. Tests of the pairwise differences are also given. Any contrast among the areas may be estimated and tested.
Produce a plot of the Receiver Operating Characteristic (ROC) curve associated with a fitted binary-response model. Label points on the ROC curve using statistic or input variable values. Identify optimal cutpoints on the ROC curve using several optimality criteria such as correct classification, efficiency, cost, and others. Plot optimality criteria against a selected variable.
The %VARTEST macro provides a one-tailed test of the null hypothesis that the variance equals a non-zero constant for normally distributed data. It also provides point- and confidence interval estimates.
NOTE: The CIBASIC option in PROC UNIVARIATE provides one- and two-sided confidence intervals for the standard deviation and variance. PROC TTEST provides a confidence interval for the standard deviation using either of two methods.
PURPOSE:
The %VARTEST macro tests the null hypothesis that the variance (or standard deviation) of a set of independent and identically normally distributed values is equal to a specified constant against an alternative that the variance (or standard deviation) exceeds the constant. The macro also provides point- and confidence interval estimates for the variance and standard deviation.