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• Mean crop production for the proposed release area wiii <br />be compared to mean crop production for the reference area using a <br />one-tailed difference of the means test. The null hypothesis for <br />the test will be that crop production on the release area is <br />greater than or equal to crop production on the reference area. <br />The model of test equation that will be used will depend upon <br />whether the variances of the two samples are equal or unequal. The <br />variances will be tested using equation 4. <br />(4) <br />F _ larger s'- <br />~a<< - <br />smaller sz <br />The Fcable value to be compared with Fca1~ will be selected <br />from a standard table of critical values for the F-distribution. <br />The test will have a = 0.1. The degrees of freedom for the <br />numerator and denominator will each be equal to n-1. If Fca1< < Ftab le <br />then the variances will be considered equal and model A of the <br />difference of the means test will be used. Otherwise, model B will <br />be used. <br />In model A of the difference of the means test, t~ai~ is <br />• determined using equation 5. <br />where: <br />(5) <br />rcalc - <br />zl - xz <br />z z <br />n~s~ + nzsz n~ + n2 <br />n~ + nz - 2 n~nz <br />xi = release area mean crop production, <br />Xz = reference area mean crop production, <br />sl' = release area sample variance, <br />sZ' = reference area sample variance, <br />nl = release area sample size, and <br />n2 = reference area sample size. <br />. (Revised 05/12/87) <br />(Revised 04/15/94) <br />2.05-25 <br />