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@ -4,7 +4,14 @@
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## 假设检验:\n",
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"## 假设检验的基本思想"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"### 假设检验\n",
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"<ul>\n",
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" <li>什么是假设:对总体参数(均值,比例等)的具体数值所作的陈述。比如,我认为新的配方的药效要比原来的更好。\n",
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" <li>什么是假设检验:先难总体的参数提出某种假设,然后利用样本的信息判断假设是否成立的过程。比如,上面的假设我是要接受还是拒绝呢\n",
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@ -15,7 +22,7 @@
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## 假设校验的应用:\n",
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"### 假设校验的应用\n",
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"<ul>\n",
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" <li>推广新的教育方案后,教学效果是否有所\n",
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" <li>提高醉驾判定为刑事犯罪后是否会使得交通事故减少\n",
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@ -26,7 +33,7 @@
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## 假设校验的基本思想\n",
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"### 假设校验的基本思想\n",
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"<img src=\"assets/20201114091803.png\" width=\"70%\">"
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]
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},
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@ -41,7 +48,7 @@
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## 显著性水平\n",
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"### 显著性水平\n",
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"<ul>\n",
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"<li>一个概率值,原假设为真时,拒绝原假设的概率,\n",
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"表示为 alpha常用取值为0.01,0.05,0.10。\n",
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@ -56,7 +63,7 @@
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## 假设检验的步骤\n",
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"### 假设检验的步骤\n",
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"<ul>\n",
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" <li>提出假设\n",
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" <li>确定适当的检验统计量。如方差验证、卡方验证等\n",
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@ -69,7 +76,14 @@
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## 原假设与备择建设\n",
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"## 左右侧检验与双侧检验"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"### 原假设与备择建设\n",
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"<ul>\n",
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" <li>待检验的假设又叫原假设,也可以叫零假设,表示为HO。(零假设其实就是表示原假设一般都是说没有差异,没有改变。。。)\n",
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" <li>与原假设对比的假设叫做备择假设,表示为H1\n",
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@ -80,18 +94,100 @@
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## 检验统计量计算检验的统计量\n",
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"### 检验统计量计算检验的统计量\n",
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"<ul>\n",
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" <li>计算检验的统计量\n",
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" <li>根据给定的显著性水平,查表得出相应的临界值"
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" <li>根据给定的显著性水平,查表得出相应的临界值\n",
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" <li>将检验统计量的值与显著性水平的临界值进行比较\n",
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" <li>得出拒绝或不拒绝原假设的结论"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"cell_type": "markdown",
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"metadata": {},
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"outputs": [],
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"source": []
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"source": [
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"### 检验中常说的小概率\n",
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"<ul>\n",
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"<li>在一次试验中,一个几乎不可能发生的事件发生的概率\n",
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" <li>在一次试验中,小概率事件一旦发生,我们就有理由拒绝原假设\n",
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" <li>小概率由我们事先确定,也就是多少的概率我们就拒绝原假设"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"### P值\n",
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"<ul>\n",
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" <li>是一个概率值\n",
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" <li>如果原假设为真,P-值是抽样分布中大于或小于样本统计量的概率\n",
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" <li>左侧检验时,P-值为曲线上方小于等于检验统计量部分的面积\n",
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" <li>右侧检验时,P-值为曲线上方大于等于检验统计量部分的面积"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"### 左侧检验与右侧检验\n",
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"<img src=\"assets/20201114095426.png\" width=\"100%\">"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"### 什么时候用左侧检验什么时候用右侧检验\n",
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"<ul>\n",
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"<li>当关键词有不得少于/低于的时候用左侧,比如灯泡的使用寿命不得少于/低于700小时\n",
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"<li>当关键词有不得多于/高于的时候用右侧,比如次品率不得多于/高于5%"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"<img src=\"assets/20201114100216.png\" width=\"70%\">"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"<ul>\n",
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" <li>单侧检验指按分布的一侧计算显著性水平概率的检验。用于检验大于、小于、高于、低于、优于、劣于等有确定性大小关系的假设检验问题。这类问题的确定是有一定的理论依据的。假设检验写作:μ1<μ2或μ1>μ2。\n",
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" <li>双侧检验指按分布两端计算显著性水平概率的检验,应用于理论上不能确定两个总体一个一定比另一个大或小的假设检验。般假设检验写作H1: μ1≠μ2"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"一例如,某种零件的尺寸,要求其平均长度为10cm,大于或小于10cm均属于不合格我们想要证明(检验)大于或小于这两种可能性中的任何一种是否成立建立的原假设与备择假设应为:\n",
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"<br>\n",
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"H0:μ = 10; H1: μ≠10"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"### 检验结果\n",
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"单侧检验\n",
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"<ul>\n",
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" <li>若p值 > α,不拒绝H0\n",
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" <li>若p值 < α,拒绝H0"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"双侧检验\n",
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"<ul>\n",
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" <li>若p值 > α/2,bu'j'j\n",
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" <li>"
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]
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}
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],
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"metadata": {
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