Confidence limits of expected Monthly Rainfall for the Agricultural College and Research Institute, Coimbatore

Abstract

Introduction From adequate statistics of rainfall dis-tribution the limits, within which the ex-pected monthly rainfall will lie, can be calculated. These are known as Confidence or Fiducial limits. The limits within which the rainfall may be expected to lie in nine years out of ten (90 per cent fiducial pro-bability) were chosen as being of practical interest to farmers by Manning (1951). Generally frequency distribution of rainfall often exhibit skewness, with the mode lower than the mean. So if no account is taken of factors such as skewness, the means and standard deviations calculated from such statistics will lack the necessary precision and may often be misleading. So it is necessary to adopt suitable method for transforming skew data to give an approximately normal distribution, from which ' Confidence Limits ' may be estimated and afterwards reconverted to the original units.