IDW距离反比加权方法，最大似然（ML）准则和最大后验概率（MAP）准则，用蒙特卡洛模拟的方法计算美式期权的价格以及基本描述。- IDW inverse distance weighting method, Maximum Likelihood (ML) criteria and maximum a posteriori (MAP) criterion, Monte Carlo simulation method of calculating the American option price