1This is file varicoli.men--2-Sample Conf. Limits for Shift in SD 2 3-------------------- 4 1. 2-Sample Confiidence Limits for Shift in Standard Deviation 5 2. 6 3. 7 4. Pre-mod Response Variable: 8 4. @CE 1 0 42 50 ? gui-vari 9 5. Post-mod Response Variable: 10 5. @CE 2 0 42 50 ? gui-vari 11 6. 12 7. Confidence level (select one): 13 8. @CE 3 1 3 23 95% limits 14 9. @CE 3 2 3 23 99% limits 1510. 1611. Number of output decimal places: 1711. @CE 4 0 42 50 ? 1812. 1913. Subset/Except/For Specification: 2014. @CE 5 0 1 50 * 2115. 2216. Compute Confidence Limits? 23-------------------- 24GR FE 25 26@IF 3 1 LET ZP = .95 27@IF 3 2 LET ZP = .99 28LET ZP2 = ZP+(1-ZP)/2 29LET ZPERC = 100*ZP 30 31LET ZN1 = NUMBER _1 _5 32LET ZN2 = NUMBER _2 _5 33LET ZDF1 = ZN1-1 34LET ZDF2 = ZN2-1 35LET ZPPFU = FPPF(ZP2,ZDF1,ZDF2) 36LET ZPPFL = FPPF(1-ZP2,ZDF1,ZDF2) 37 38LET ZM1 = MEAN _1 _5 39LET ZM2 = MEAN _2 _5 40LET ZSD1 = SD _1 _5 41LET ZSD2 = SD _2 _5 42LET ZSTAT = ZSD1/ZSD2 43LET ZLOWER = ZSTAT*SQRT(1/ZPPFU) 44LET ZUPPER = ZSTAT*SQRT(1/ZPPFL) 45@IF 2 1 LET ZLOWSKL = 0 46@IF 2 1 LET ZUPPSKL = ZSTAT*SQRT(1/FPPF(.95,ZDF1,ZDF2)) 47@IF 2 2 LET ZLOWSKR = ZSTAT*SQRT(1/FPPF(.05,ZDF1,ZDF2)) 48@IF 2 2 LET ZUPPSKR = 10**10 49 50IF ZLOWER < 0 51 LET ZLOWER = 0 52END IF 53 54LET ZINC = (ZUPPER-ZLOWER)/200 55LET ZWIDTH4 = (ZUPPER-ZLOWER)/4 56LET ZLOWER2 = ZLOWER-ZWIDTH4 57LET ZUPPER2 = ZUPPER+ZWIDTH4 58 59IF ZLOWER2 < 5 60 LET ZLOWER2 = .1 61END IF 62 63. With thanks to Mark Vangel 64LET FUNCTION ZF = FPDF((ZSTAT**2)/(ZZ**2),ZDF1,ZDF2) 65LET FUNCTION ZF2 = 2*(ZSTAT**2)/ZZ**3 66PLOT ZF*ZF2 FOR ZZ = ZLOWER2 ZINC ZUPPER2 AND 67PLOT 0 FOR ZZ = ZLOWER2 ZINC ZUPPER2 68 69JUSTIFICATION CENTER 70LET ZZ = ZSTAT; LET ZPDFSTAT = ZF*ZF2 71LET ZZ = ZLOWER; LET ZPDFLOWE = ZF*ZF2 72LET ZZ = ZUPPER; LET ZPDFUPPE = ZF*ZF2 73 74DRAWDDDS ZSTAT ZPDFSTAT ZSTAT 10 75DRAWDDDS ZLOWER ZPDFLOWE ZLOWER 5 76DRAWDDDS ZUPPER ZPDFUPPE ZUPPER 5 77 78MOVEDS ZSTAT 6; TEXT ^ZSTAT 79MOVEDS ZLOWER 1; TEXT ^ZLOWER 80MOVEDS ZUPPER 1; TEXT ^ZUPPER 81 82@IF 4 0 SET WRITE DECIMALS _4 83CAPTURE ZZZZJUNK.DAT 84WRITE "^ZPERC Confidence Limits for sigma1/sigma2" 85WRITE " " 86WRITE " Pre-mod Post-mod" 87WRITE "Number of Obs. = ^ZN1 ^ZN2" 88WRITE "Estimated Means = ^ZM1 ^ZM2" 89WRITE "Estimated St. devs. = ^ZSD1 ^ZSD2" 90WRITE " " 91WRITE "Estimated Ratio = s1/s2 = ^ZSTAT" 92WRITE "Estimated Lower Limit = ^ZLOWER" 93WRITE "Estimated Upper Limit = ^ZUPPER" 94WRITE ZPERC ZN1 ZN2 ZSTAT ZSDSTAT ZLOWER ZUPPER 95END OF CAPTURE 96LIST ZZZZJUNK.DAT 97-------------------- 98