正态分布与标准正态分布
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0.5160.51990.52390.52790.53190.53590.1
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0.54380.54780.55170.55570.55960.56360.56750.57140.57530.20.57930.58320.58710.5910.59480.59870.60260.60640.61030.61410.30.61790.62170.62550.62930.63310.63680.64060.64430.6480.65170.40.65540.65910.66280.66640.670.67360.67720.68080.68440.68790.50.69150.6950.69850.70190.70540.70880.71230.71570.7190.72240.60.72570.72910.73240.73570.73890.74220.74540.74860.75170.75490.70.7580.76110.76420.76730.77030.77340.77640.77940.78230.78520.80.78810.7910.79390.79670.79950.80230.80510.80780.81060.81330.90.81590.81860.82120.82380.82640.82890.83150.8340.83650.838910.84130.84380.84610.84850.85080.85310.85540.85770.85990.86211.10.86430.86650.86860.87080.87290.87490.8770.8790.8810.8831.20.88490.88690.88880.89070.89250.89440.89620.8980.89970.90151.30.90320.90490.90660.90820.90990.91150.91310.91470.91620.91771.40.91920.92070.92220.92360.92510.92650.92780.92920.93060.93191.50.93320.93450.93570.9370.93820.93940.94060.94180.9430.94411.60.94520.94630.94740.94840.94950.95050.95150.95250.95350.95451.70.95540.95640.95730.95820.95910.95990.96080.96160.96250.96331.80.96410.96480.96560.96640.96710.96780.96860.96930.970.97061.90.97130.97190.97260.97320.97380.97440.9750.97560.97620.976720.97720.97780.97830.97880.97930.97980.98030.98080.98120.98172.10.98210.98260.9830.98340.98380.98420.98460.9850.98540.98572.20.98610.98640.98680.98710.98740.98780.98810.98840.98870.9892.30.98930.98960.98980.99010.99040.99060.99090.99110.99130.99162.40.99180.9920.99220.99250.99270.99290.99310.99320.99340.99362.50.99380.9940.99410.99430.99450.99460.99480.99490.99510.99522.60.99530.99550.99560.99570.99590.9960.99610.99620.99630.99642.70.99650.99660.99670.99680.99690.9970.99710.99720.99730.99742.80.99740.99750.99760.99770.99770.99780.99790.99790.9980.99812.90.99810.99820.99820.99830.99840.99840.99850.99850.99860.998630.99870.9990.99930.99950.99970.99980.99980.99990.999913.10.9990320.9990650.9990960.9991260.9991550.9991840.9992110.9992380.9992640.9992893.20.9993130.9993360.9993590.9993810.9994020.9994230.9994430.9994620.9994810.9994993.30.9995170.9995340.9995500.9995660.9995810.9995960.9996100.9996240.9996380.9996603.40.9996630.9996750.9996870.9996980.9997090.9997200.9997300.9997400.9997490.9997603.50.9997670.9997760.9997840.9997920.9998000.9998070.9998150.9998220.9998280.9998853.60.9998410.9998470.9998530.9998580.9998640.9998690.9998740.9998790.9998830.9998803.70.9998920.9998960.9999000.9999040.9999080.9999120.9999150.9999180.9999220.9999263.80.9999280.9999310.9999330.9999360.9999380.9999410.9999430.9999460.9999480.9999503.90.9999520.9999540.9999560.9999580.9999590.9999610.9999630.9999640.9999660.99996740.9999680.9999700.9999710.9999720.9999730.9999740.9999750.9999760.9999770.9999784.10.9999790.9999800.9999810.9999820.9999830.9999830.9999840.9999850.9999850.9999864.20.9999870.9999870.9999880.9999880.9999890.9999890.9999900.9999900.9999910.9999914.30.9999910.9999920.9999920.9999300.9999930.9999930.9999930.9999940.9999940.9999944.40.9999950.9999950.9999950.9999950.9999960.9999960.9999961.0000000.9999960.9999964.50.9999970.9999970.9999970.9999970.9999970.9999970.9999970.9999980.9999980.9999984.60.9999980.9999980.9999980.9999980.9999980.9999980.9999980.9999980.9999990.9999994.70.9999990.9999990.9999990.9999990.9999990.9999990.9999990.9999990.9999990.9999994.80.9999990.9999990.9999990.9999990.9999990.9999990.9999990.9999990.9999990.9999994.91.0000001.0000001.0000001.0000001.0000001.0000001.0000001.0000001.0000001.0000000.040.050.060.07标准正态分布函数表(形式1)
标准正态分布和正态分布的关系
正态分布是概率统计学中非常重要的概率分布之一,其在自然界、社会科学、医学等领域都有着广泛的应用。而标准正态分布则是正态分布中的一种特殊情况,下面我们来探讨一下这两者之间的关系。
一、 正态分布的定义
正态分布也称高斯分布,是指具有以下特征的实数随机变量的概率分布:
(1)其概率密度函数图像呈现钟形曲线,左右两端渐进于x轴,中央最高峰点对应着期望值μ。
(2)当x值等于μ时,曲线取极大值。
(3)随着x值与μ的距离增加,曲线高度逐渐下降。
(4)分布的形状参数是标准差σ。
二、标准正态分布的定义
标准正态分布(Standard normal distribution)是均值μ为0,标准差σ为1的正态分布。其概率密度函数可表示为:
φ(x)=1/√(2π) ×e(-x²/2)
其中,e表示自然常数,π表示圆周率,φ表示概率密度函数。
三、标准正态分布和正态分布之间的关系
标准正态分布和正态分布有着密切的关系,正态分布可以通过标准正态分布进行转化。设X是一个正态分布随机变量,其均值为μ,标准差为σ,那么可以通过以下公式将其转化为标准正态分布随机变量Z:
Z = (X-μ)/σ
因此,在统计分析中,我们通常将一些非标准正态分布的随机变量转化为标准正态分布(这个过程又称为正态化),以方便进行进一步数学推导。
使用标准正态分布,我们可以计算出一个随机变量落在某个区间内的概率,这也是正态分布广泛应用于实际问题中的关键所在,例如在医疗领域中,我们可以根据某种疾病的实际情况,得到一个其患病率呈正态分布的模型,然后基于患病率和某种药物对此疾病的治疗效果,我们就可以通过标准正态分布来计算出治疗成功的概率。
四、总结
正态分布和标准正态分布是两个非常重要的概率分布,它们在实际应用中具有广泛的用途。标准正态分布是正态分布中的一种特殊情况,两者之间有着密切的关系。通过标准正态分布,我们可以计算出一个随机变量落在某个区间内的概率,进而可以应用于许多实际的统计分析问题中。
标准正态分布表
φ( - x ) = 1 –φ( x )
x 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09
0 0.500 0 0.504 0 0.508 0 0.512 0 0.516 0 0.519 9 0.523 9 0.527 9 0.531 9 0.535 9
0.1 0.539 8 0.543 8 0.547 8 0.551 7 0.555 7 0.559 6 0.563 6 0.567 5 0.571 4 0.575 3
0.2 0.579 3 0.583 2 0.587 1 0.591 0 0.594 8 0.598 7 0.602 6 0.606 4 0.610 3 0.614 1
0.3 0.617 9 0.621 7 0.625 5 0.629 3 0.633 1 0.636 8 0.640 4 0.644 3 0.648 0 0.651 7
0.4 0.655 4 0.659 1 0.662 8 0.666 4 0.670 0 0.673 6 0.677 2 0.680 8 0.684 4 0.687 9
0.5 0.691 5 0.695 0 0.698 5 0.701 9 0.705 4 0.708 8 0.712 3 0.715 7 0.719 0 0.722 4
0.6 0.725 7 0.729 1 0.732 4 0.735 7 0.738 9 0.742 2 0.745 4 0.748 6 0.751 7 0.754 9
0.7 0.758 0 0.761 1 0.764 2 0.767 3 0.770 3 0.773 4 0.776 4 0.779 4 0.782 3 0.785 2
0.8 0.788 1 0.791 0 0.793 9 0.796 7 0.799 5 0.802 3 0.805 1 0.807 8 0.810 6 0.813 3
标准正态分布+标准正态分布概率表+分布函数+积分
X~N(µ,σ²):⼀般正态分布:均值为µ、⽅差为σ²
/zhanghongxian123/article/details/39008493
对于标准正态分布来说,存在⼀张表,称为:标准正态分布表:
该表计算的是:P(X<=x)【某个数落在某个[-@,x]】的概率。也就是下⾯阴影图形所⽰的⾯积:
如果x=1.96.则将1.96拆分为1.9和0.06.横轴1.9和纵轴0.06的交汇处:0.975.就是x<=1.96的概率。
也就是说,标准正态分布图形与x=a所围⾯积等于x<=a(某个值落在组数据的某个区间的)的概率。
例如,对于某组成绩组数据,服从平均值为45,标准差是10的正态分布:
那么,任抽取⼀个同学的成绩,它的分数在63以上的概率为多少【落在[63,+@]区间的概率】?
也就是图中斜线的⾯积!
如果对f(x)做-@到63的计分,在⽤1减去它。计分⽐较⿇烦。那么,将组数据标准化,标准化后的数据服从标准整体分布~!就将63数据标准化。
对63标准化就是“距离/标准差”
(63-45)/10=1.8。就是说,在标准整体分布中,得分落在区间[1.8,+@]的概率是:1-0.9641=0.0359=3.59%
也就说,对于正态分布,想求得数据区间概率(⾯积),将“分割点”标准化即可,查表即可!!
以下描述是等同的:
全体学⽣,分数超过63分的同学占3.59%;
全体学⽣,任取⼀个分数⼤于63分的概率为3.59%;
全体学⽣,任取⼀个分数,标准计分⼤于1.8的概率为3.59%;