RT Journal A1 Murray DS T1 STatistical method for determination of ovulation time in women JF Journal of the American Medical Association JO Journal of the American Medical Association YR 1959 FD May 2 VO 170 IS 1 SP 42 OP 43 DO 10.1001/jama.1959.63010010001009 UL http://dx.doi.org/10.1001/jama.1959.63010010001009 AB The data developed by Sevag and Colton for their paper "Simple Chemical Method for the Determination of Ovulation Time in Women," which appears in this issue of The Journal, page 13, offer the opportunity to test the possibility of applying a simple technique of linear correlation to estimate the day of ovulation. The data studied were limited to normal full-term pregnancies where conception was achieved by therapeutic donor insemination. In addition, all patients having menstrual cycles of less than 23 or more than 34 days were eliminated from consideration. Data beyond these limits appeared to be sufficiently unusual as to warrant their exclusion from a study that seeks to determine whether any typical relation exists between the length of the menstrual cycle and the day of ovulation.Sixty-seven patients met the criteria concerning manner of conception and length of the menstrual cycle. These patients had a mean cycle length of