Document OdNv5w4O2gN53dZpebmdJ44L

9.0.36 Jeffery- Rd. Great Palls, Va - 22066 November 19, 1976 Robert A. Kehoe, M.D. Department of Environmental Health Kettering Laboratory University of Cincinnati Medical Center 3223 Eden Ave. Cincinnati, Ohio 45267 Dear Dr. Kehoe: I am briefly responding to your letter of November 12 con cerning the corrections that we have made in the data. The data we started the project with came from two computer tapes supplied to us by Bernie Sobel. These tapes were apparently made from computer cards which contained data keypunched directly from the original data sheets. We transferred the data on these tapes to computer cards which we then tried to use for making graphs and calculations. We also keypunched new cards for data that had not already been punched. Because the data was punched using different formats (different data in different columns) making them difficult to use, we transferred the data onto new computer cards giving them all the same format. We then used the. new cards for all of the data processing which led to my preliminary report (progress report) dated October 24, 1975. This report was put together in a rush in order to make the data available to Ethyl Corporation for possible use in some hearings in California. ' I explained in my report and at our meeting with Drs. Zavon, Ter Haar and Sobel that I had not had a chance to compare the data in the report with the original data in your files. Up to that time my staff and I had about all we could do to merely get the data processed to the point at which we could begin to examine the data critically. I have xeroxed copies of most of the original data with me in Virginia. The original data is indeed remarkably precise and correctly recorded as you say in your letter. There are, however, a few errors in the numbering of the days, even in the original data. These errors are minor compared to the errors in keypunching. Very briefly, we found that days were misnumbered, blocks of data had been left out, there were decimal point errors and also erroneously punched data. At the time of the report we had 80 different experimental phases. We now have 102. K 0000452 Robert A. Kehoe, M.D. November 19, 1976 2- In addition to making these corrections, we have also keypunched the chamber conditions (times of exposure, lead concentrations, deposition data, etc.) in order to obtain more accurate numbers of these parameters. Wec had previously used the data from a table compiled by Larry S,chafer. Larry had emphasized the "unofficial" status of the data in his tables. We still do not have access to the original particle size distribution data that Larry summarized in his table. We have also had to weed out what appeared to be aberrant data using plus or minus four standard deviations as an acceptable range. We have only recently (last week) completed the computer plots which now make it possible for us to visually examine the hew data. They: appear to be in good order. I hope that this adequately explains the references to the corrections that we have made. Best Regards, SBG/ra Stanley B. Gross, Ph.D. K 0000453