时的最小样本数是多少? 取N→∞时的t值为最初t值(1.96),以此算出N的初值。用对应于N初值的t值 代入,不断叠代,直至算得的N值不变,此N值即为最小样本数。 1,96×0.034 在t表中查得tos,=2,78,代入公式: N=2.78×0.034: 9.9≈10 在t表中查得ta0,=2.26,代入公式 2.26×0.034 N =6.56≈7 在t表中查得t(o0,6)=2.45,代入公式 2.45×0.034 在t表中查得t(0,n=2,36,代入公式: 36×0.034 7.2 为了使平均值的误差在士003范围内,至少需要抽取8个样本。 410t分布的分位数 n0.100.0500.0250.0100.005n0.100.0500.0250.0100.005 3.0786.3141270631.82163657181.3301.7342.1012.5522.878 21.88629204.30369659.925191.3281.7292.0932.5392,861 31.6382.3533.18245415.841201.3251.7252.0862.5282 1.53321322.7763.747.4,664|211.3231.7 0802.5182.93 51.4762.0152.5713.3654.031|221.3211.7172.0742.5082.819 61.4401.9432.4473.1433.701231.3191.7142.0692.5002.807 71.4151.895236529983.461241.3181.7112.0642.4922.79 81.3971.8602.3062.8963355251.3161.7082.0602.4852.787 91.3831.8332.2622.8213,2521261.3151 2.0562.4792.77 101.3721,8122.2282.7643161271.3141.7032.0522.4732.71 111.3631.7692.2012,7183.101281.3131.7012.0482.467 121.3561·78221792.6813.054291.3111.6992.0452.462 131.3501.7172.1602.6503011301.3101,6972.0422.4572.750 141.3451.7612.1452.624 771401 1.6842.0212.4232 151.34117532,1312.6022.847601.2961.6712.000.390 161371.7462.102583291101.2891.65818028582617 171.3331.7402.1102.5672.898 a-0.995、0.990、0.975、0.950和0.900是由tn,1-=-t,得到的 ·196·