正态分布是连续概率分布。也称为高斯分布。
正态分布密度函数f（z）被称为钟形曲线，因为它具有类似于钟形的形状。
标准正态分布表用于查找f（z）函数下的面积，以便找到指定分布范围的概率。
正态分布函数标准正态分布函数标准正态分布表正态分布函数当随机变量X具有正态分布时，
正态分布的概率密度函数和累积分布函数：
概率密度函数（pdf）概率密度函数由下式给出：
X是随机变量。
μ是平均值。
σ是标准偏差（std）值。
e = 2.7182818 ...恒定。
π= 3.1415926 ...恒定
累积分布函数累积分布函数由下式给出：
X是随机变量。
μ是平均值。
σ是标准偏差（std）值。
e = 2.7182818 ...恒定。
π= 3.1415926 ...恒定
标准正态分布函数什么时候
然后是标准正态分布的概率密度函数和累积分布函数：
概率密度函数累积分布函数标准正态分布表z Φ（z）φ（z）0.000.50000.39890.010.50400.39890.020.50800.39890.030.51200.39880.040.51600.39860.050.51990.39840.060.52390.39820.070.52790.39800.080.53190.39770.090.53590.39730.100.53980.39700.110.54380.39650.120.54780.39610.130.55170.39560.140.55570.39510.150.55960.39450.160.56360.39390.170.56750.39320.180.57140.39250.190.57530.39180.200.57930.39100.210.58320.39020.220.58710.38940.230.59100.38850.240.59480.38760.250.59870.38670.260.60260.38570.270.60640.38470.280.61030.38360.290.61410.38250.300.61790.38140.310.62170.38020.320.62550.37900.330.62930.37780.340.63310.37650.350.63680.37520.360.64060.37390.370.64430.37250.380.64800.37120.390.65170.36970.400.65540.36830.410.65910.36680.420.66280.36530.430.66640.36370.440.67000.36210.450.67360.36050.460.67720.35890.470.68080.35720.480.68440.35550.490.68790.35380.500.69150.35210.510.69500.35030.520.69850.34850.530.70190.34670.540.70540.34480.550.70880.34290.560.71230.34100.570.71570.33910.580.71900.33720.590.72240.33520.600.72570.33320.610.72910.33120.620.73240.32920.630.73570.32710.640.73890.32510.650.74220.32300.660.74540.32090.670.74860.31870.680.75170.31660.690.75490.31440.700.75800.31230.710.76110.31010.720.76420.30790.730.76730.30560.740.77040.30340.750.77340.30110.760.77640.29890.770.77940.29660.780.78230.29430.790.78520.29200.800.78810.28970.810.79100.28740.820.79390.28500.830.79670.28270.840.79950.28030.850.80230.27800.860.80510.27560.870.80780.27320.880.81060.27090.890.81330.26850.900.81590.26610.910.81860.26370.920.82120.26130.930.82380.25890.940.82640.25650.950.82890.25410.960.83150.25160.970.83400.24920.980.83650.24680.990.83890.24441.000.84130.24201.010.84380.23961.020.84610.23711.030.84850.23471.040.85080.23231.050.85310.22991.060.85540.22751.070.85770.22511.080.85990.22271.090.86210.22031.100.86430.21791.110.86650.21551.120.86860.21311.130.87080.21071.140.87290.20831.150.87490.20591.160.87700.20361.170.87900.20121.180.88100.19891.190.88300.19651.200.88490.19421.210.88690.19191.220.88880.18951.230.89070.18721.240.89250.18491.250.89440.18261.260.89620.18041.270.89800.17811.280.89970.17581.290.90150.17361.300.90320.17141.310.90490.16911.320.90660.16691.330.90820.16471.340.90990.16261.350.91150.16041.360.91310.15821.370.91470.15611.380.91620.15391.390.91770.15181.400.91920.14971.410.92070.14761.420.92220.14561.430.92360.14351.440.92510.14151.450.92650.13941.460.92790.13741.470.92920.13541.480.93060.13341.490.93190.13151.500.93320.12951.510.93450.12761.520.93570.12571.530.93700.12381.540.93820.12191.550.93940.12001.560.94060.11821.570.94180.11631.580.94290.11451.590.94410.11271.600.94520.11091.610.94630.10921.620.94740.10741.630.94840.10571.640.94950.10401.650.95050.10231.660.95150.10061.670.95250.09891.680.95350.09731.690.95450.09571.700.95540.09401.710.95640.09251.720.95730.09091.730.95820.08931.740.95910.08781.750.95990.08631.760.96080.08481.770.96160.08331.780.96250.08181.790.96330.08041.800.96410.07901.810.96490.07751.820.96560.07611.830.96640.07481.840.96710.07341.850.96780.07211.860.96860.07071.870.96930.06941.880.96990.06811.890.97060.06691.900.97130.06561.910.97190.06441.920.97260.06321.930.97320.06201.940.97380.06081.950.97440.05961.960.97500.05841.970.97560.05731.980.97610.05621.990.97670.05512.000.97720.05402.010.97780.05292.020.97830.05192.030.97880.05082.040.97930.04982.050.97980.04882.060.98030.04782.070.98080.04682.080.98120.04592.090.98170.04492.100.98210.04402.110.98260.04312.120.98300.04222.130.98340.04132.140.98380.04042.150.98420.03962.160.98460.03872.170.98500.03792.180.98540.03712.190.98570.03632.200.98610.03552.210.98640.03472.220.98680.03392.230.98710.03322.240.98750.03252.250.98780.03172.260.98810.03102.270.98840.03032.280.98870.02972.290.98900.02902.300.98930.02832.310.98960.02772.320.98980.02702.330.99010.02642.340.99040.02582.350.99060.02522.360.99090.02462.370.99110.02412.380.99130.02352.390.99160.02292.400.99180.02242.410.99200.02192.420.99220.02132.430.99250.02082.440.99270.02032.450.99290.01982.460.99310.01942.470.99320.01892.480.99340.01842.490.99360.01802.500.99380.01752.510.99400.01712.520.99410.01672.530.99430.01632.540.99450.01582.550.99460.01542.560.99480.01512.570.99490.01472.580.99510.01432.590.99520.01392.600.99530.01362.610.99550.01322.620.99560.01292.630.99570.01262.640.99590.01222.650.99600.01192.660.99610.01162.670.99620.01132.680.99630.01102.690.99640.01072.700.99650.01042.710.99660.01012.720.99670.00992.730.99680.00962.740.99690.00932.750.99700.00912.760.99710.00882.770.99720.00862.780.99730.00842.790.99740.00812.800.99740.00792.810.99750.00772.820.99760.00752.830.99770.00732.840.99770.00712.850.99780.00692.860.99790.00672.870.99790.00652.880.99800.00632.890.99810.00612.900.99810.00602.910.99820.00582.920.99820.00562.930.99830.00552.940.99840.00532.950.99840.00512.960.99850.00502.970.99850.00482.980.99860.00472.990.99860.00463.000.99870.00443.010.99870.00433.020.99870.00423.030.99880.00403.040.99880.00393.050.99890.00383.060.99890.00373.070.99890.00363.080.99900.00353.090.99900.00343.100.99900.00333.110.99910.00323.120.99910.00313.130.99910.00303.140.99920.00293.150.99920.00283.160.99920.00273.170.99920.00263.180.99930.00253.190.99930.00253.200.99930.00243.210.99930.00233.220.99940.00223.230.99940.00223.240.99940.00213.250.99940.00203.260.99940.00203.270.99950.00193.280.99950.00183.290.99950.00183.300.99950.00173.310.99950.00173.320.99950.00163.330.99960.00163.340.99960.00153.350.99960.00153.360.99960.00143.370.99960.00143.380.99960.00133.390.99970.00133.400.99970.00123.410.99970.00123.420.99970.00123.430.99970.00113.440.99970.00113.450.99970.00103.460.99970.00103.470.99980.00103.480.99980.00093.490.99980.00093.500.99980.00093.510.99980.00083.520.99980.00083.530.99980.00083.540.99980.00083.550.99980.00073.560.99980.00073.570.99980.00073.580.99980.00073.590.99980.00063.600.99980.00063.610.99980.00063.620.99990.00063.630.99990.00053.640.99990.00053.650.99990.00053.660.99990.00053.670.99990.00053.680.99990.00053.690.99990.00043.700.99990.00043.710.99990.00043.720.99990.00043.730.99990.00043.740.99990.00043.750.99990.00043.760.99990.00033.770.99990.00033.780.99990.00033.790.99990.00033.800.99990.00033.810.99990.00033.820.99990.00033.830.99990.00033.840.99990.00033.850.99990.00023.860.99990.00023.870.99990.00023.880.99990.00023.890.99990.00023.901.00000.00023.911.00000.00023.921.00000.00023.931.00000.00023.941.00000.00023.951.00000.00023.961.00000.00023.971.00000.00023.981.00000.00013.991.00000.0001标准正态分布图（零以上）
也可以看看概率分布统计符号正态分布-维基百科
