实验要求：
1.　　以身高为例，画出男女生身高的直方图并做对比；
2.　　采用最大似然估计方法，求男女生身高以及体重分布的参数；
3.　　采用贝叶斯估计方法，求男女生身高以及体重分布的参数（假定方差已知，作业请注明自己选定的一些参数情况）；
4.　　采用最小错误率贝叶斯决策，画出类别判定的决策面。并判断某样本的身高体重分别为(160,45)时应该属于男生还是女生？为(178,70)时呢？(Experimental requirements:

1. take height as an example, draw the height histogram of male and female students, and make a comparison;

2. the maximum likelihood estimation method was used to calculate the height and weight distribution parameters of male and female students;

3. Bayesian estimation method is used to find the parameters of height and weight distribution of male and female students (assuming variance is known, please indicate some parameters selected by homework);

4., the Bayes decision with minimum error rate is used to draw the decision surface of category decision. And determine the height and weight of a sample respectively (160,45), should belong to the boys or girls? What about (178,70)?)