1. NAME AND TITLE

LOGNORML: Lognormal Probability Analysis Code System for Estimating Doses in Epidemiologic Studies.

In May 1991 LPROBIT was packaged as PSR-307. The October 1991 update obsoletes LPROBIT with the release of LOGNORML. LOGNORML corrects an error, handles grouped as well as individual data, and includes other improvements.

2. CONTRIBUTOR

University of Pittsburgh, Pittsburgh, Pennsylvania.

3. CODING LANGUAGE AND COMPUTER

Microsoft QuickBASIC 4.5 or MS-DOS QBASIC; IBM PC and IBM PS/2.

4. NATURE OF PROBLEM SOLVED

LOGNORML performs log-probability analyses and computes collective and average doses missed due to the minimum detectable dose problem. It can be used for general lognormal analysis and for analysis of occupational dose distributions. It can handle both grouped and ungrouped data. LOGNORML will work with any data set that is expected to be distributed normally.

5. METHOD OF SOLUTION

The program is interactive. LOGNORML asks whether keyboard input or file input is desired. Missing or below detectable doses are entered as zeroes. All but the first option require that the dose rate be sorted in ascending order. Simple summary statistics are computed. LOGNORML reads an input file called NORML.DAT of the integral of the normal distribution vs. the standard normal deviate. Cumulative probabilities for the sorted user data are used for the standard normal deviate. LOGNORML then performs linear regressions on the natural logarithms of the dose values and the standard normal deviate using uniform weighting and Finney's weighting.

6. RESTRICTIONS OR LIMITATIONS

None noted.

7. TYPICAL RUNNING TIME

The program is interactive and response time is very fast. Run time depends on file size. 155 data points require only about 38 seconds on a 16 MHz PC 386 with a 80387 math coprocessor.

8. COMPUTER HARDWARE REQUIREMENTS

The code runs on IBM PC's and compatibles and the IBM PS/2 Models 50, 60, 70.

9. COMPUTER SOFTWARE REQUIREMENTS

The code is written in Microsoft QuickBASIC 4.5. Alternately, MS-DOS QBasic Version 5.0 can be used.

10. REFERENCES

``Below Detection Limit References'' (October 1991).

Daniel J. Strom, ``LOGNORML: Log-Probability Analysis,'' Informal Notes, University of Pittsburgh, Pittsburgh, Pennsylvania (Sept. 4, 1991).

Daniel J. Strom, ``Estimating Individual and Collective Doses to Groups with Less Than Detectable Doses: A Method for Use in Epidemiologic Studies,'' Health Physics 51(4): 437-445 (October 1986).

11. CONTENTS OF CODE PACKAGE

Included are the referenced documents and one DS/DD (360 K) 5.25 inch diskette which contains the source code, executable file, sample input and output, and documentation.

12. DATE OF ABSTRACT

May 1991; revised October 1991.