NAME: Three_sigma PURPOSE: For array y, return min and max values within 3 standard deviations from the mean CALLING SEQUENCE: res=three_sigma(y) INPUTS: y = array of 4 or more elements KEYWORD PARAMETERS: MODIFIED = use modified sigma which uses kurt. & skew. results in a more liberal acceptance of data OUTPUTS: structure containing: ymin = minimum value within 3 stdev's of mean ymax = maximum value within 3 stdev's of mean MODIFICATION HISTORY: 05/2006 This is a function version of the procedure semiminmax.pro We've noticed problems when using semiminmax: When calling it a second time from within a routine the values of ymin,ymax from the first call were passed back into semiminmax since now they were existing variables. Calling this program as a function solves this problem. Copyright 1996-2013 United States Government as represented by the Administrator of the National Aeronautics and Space Administration. All Rights Reserved.