第三篇醫(yī)學(xué)統(tǒng)計(jì)學(xué)方法-預(yù)覽頁(yè)
【正文】 何標(biāo)準(zhǔn)差 適用于對(duì)數(shù)正態(tài)或近似對(duì)數(shù)正 態(tài)分布資料 3. 中位數(shù) 四分位數(shù)間距 或百分位數(shù) 分布不規(guī)則的資料，分散程度 大的資料 24 變異系數(shù) (coefficient of variation， CV): 若比較度量單位不同或均數(shù)相差懸殊的兩組 (或幾組 )觀察值的變異度，則需用變異系數(shù)為相互比較的指標(biāo)。 適用于： (1) 比較單位不同的多組資料的變異度。 這條正態(tài)分布 曲線的特點(diǎn)為 ： ① 高峰位于中央均數(shù)所在處、兩側(cè)逐漸降低 ； ② 左右對(duì)稱 ； ③ 曲線 在無(wú)窮遠(yuǎn)處 與橫軸相交。 ? ? ? ?212 ( 9 1 7 )12uf u u e u????? ? ? ? ? ? ? ?為實(shí)際應(yīng)用方便，將一般正態(tài)分布轉(zhuǎn)換為標(biāo)準(zhǔn)正態(tài)分布。 X u 30 圖 94 正態(tài)曲線與標(biāo)準(zhǔn)正態(tài)曲線的面積分布 二、正態(tài)曲線下面積的分布規(guī)律 :用積分法求得。 xx． 32 三、醫(yī)學(xué)參考值范圍的估計(jì) ㈠參考值范圍 (reference range)的意義 參考值 是指正常人體或動(dòng)物的各種生理常數(shù)，正常人體液和排泄物中某種生理生化指標(biāo)或某種元素的含量，以及人體對(duì)各種試驗(yàn)的正常反應(yīng)值等。排除患有影響所研究指標(biāo)的疾病和有關(guān)因素的同質(zhì)人群。 ④判斷是否需要分組確定參考值范圍。 80%， 90%， 95%， 99%。用百分位數(shù) 法計(jì)算單側(cè) 95%參考值范圍的上界值。 39 u .00 .01 .02 .03 .04 .05 .06 .07 .08 .09 .0013 .0013 .0013 .0012 .0012 .0011 .0011 .0011 .0010 .0010 .0019 .0018 .0018 .0017 .0016 .0016 .0015 .0015 .0014 .0014 .0026 .0025 .0024 .0023 .0023 .0022 .0021 .0021 .0020 .0019 .0035 .0034 .0033 .0032 .0031 .0030 .0029 .0028 .0027 .0026 .0047 .0045 .0144 .0043 .0041 .0040 .0039 .0038 .0037 .0036 .0062 .0060 .0059 .0057 .0055 .0054 .0052 .0051 .0049 .0048 .0082 .0080 .0078 .0075 .0073 .0071 .0069 .0068 .0066 .0064 .0107 .0104 .0102 .0099 .0096 .0094 .0091 .0089 .0087 .0084 .0139 .0136 .0132 .0129 .0125 .0122 .0119 .0116 .0113 .0110 .0179 .0174 .0170 .0166 .0162 .0158 .0154 .0150 .0146 .0143 .0228 .0222 .0217 .0212 .0207 .0202 .0197 .0192 .0188 .0183 .0287 .0281 .0274 .0268 .0262 .0256 .0250 .0244 .0239 .0233 .0359 .0351 .0344 .0336 .0329 .0322 .0314 .0307 .0301 .0294 .0446 .0436 .0427 .0418 .0409 .0401 .0392 .0384 .0375 .0367 .0548 .0537 .0526 .0516 .0505 .0495 .0485 .0475 .0465 .0455 .0668 .0655 .0643 .0630 .0618 .0606 .0594 .0582 .0571 .0559 .0808 .0793 .0778 .0764 .0749 .0735 .0721 .0798 .0694 .0681 表 98 標(biāo)準(zhǔn)正態(tài)分布曲線下的面積 自 ∞到 u的面積 Φ(∞, u)， Φ(u, +∞)=1Φ(∞,u) 40 .0808 .0793 .0778 .0764 .0749 .0735 .0721 .0798 .0694 .0681 .0968 .0951 .0934 .0918 .0901 .0885 .0869 .0853 .0838 .0823 .1151 .1131 .1112 .1093 .1075 .1056 .1038 .1020 .1003 .0985 .1357 .1335 .1314 .1292 .1271 .1251 .1230 .1210 .1190 .1170 .1587 .1562 .1539 .1515 .1492 .1469 .1446 .1423 .1401 .1379 .1841 .1814 .1788 .1762 .1736 .1711 .1685 .1660 .1635 .1611 .2119 .2090 .2061 .2033 .2020 .1977 .1949 .1922 .1894 .1867 .2420 .2339 .2358 .2327 .2296 .2266 .2236 .2206 .2177 .2148 .2743 .2709 .2676 .3643 .2611 .2578 .2546 .2514 .2483 .2451 .3085 .3050 .3015 .2981 .2946 .2912 .2877 .2843 .2810 .2776 .3446 .3409 .3372 .3336 .3300 .3264 .3228 .3192 .3156 .3121 .3821 .3783 .3745 .3707 .3669 .3632 .3594 .3557 .3520 .3483 .4207 .4168 .4129 .4090 .4052 .4013 .3974 .3936 .3897 .3859 .4602 .4562 .4522 .4483 .4443 .4404 .4364 .4325 .4286 .4247 .5000 .4960 .4920 .4880 .4840 .4801 .4761 .4721 .4681 .4641 u .00 .01 .02 .03 .04 .05 .06 .07 .08 .0
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