参考资料
[1] 盛骤, 谢式千, 潘承毅. 概率论和数理统计[J]. 2001.
[2] https://en.wikipedia.org/wiki/Maximum_likelihood
[3] https://www.youtube.com/watch?v=fvNUUJuFXM0
[4] https://en.wikipedia.org/wiki/Independent_and_identically_distributed_random_variables
[5] http://www.cnblogs.com/liliu/archive/2010/11/22/1883702.html
最大似然估计（Maximum Likelihood Estimation）
原文：http://blog.csdn.net/livecoldsun/article/details/41147627
