一、教材分析1.教材的地位和作用方差是概率论和数理统计的重要概念之一,是反映随机变量取值分布的特征数,学习方差将为今后学习概率统计知识做铺垫.同时,它在市场预测,经济统计,风险与决策等领域有着广泛的应用,对今后学习数学及相关学科产生深远的影响.2.教学重点与难点重点:离散型随机变量方差的概念及其实际含义. First, the textbook analysis 1 textbook status and role of variance is one of the important concepts of probability theory and mathematical statistics is to reflect the random variable value distribution of the number of features, learning variance will pave the way for future learning probability and statistics knowledge.At the same time, it In the field of market forecasting, economic statistics, risk and decision-making, it has a wide range of applications and will have far-reaching impact on the future of learning mathematics and related subjects.2.Teaching key and difficult points: The concept of discrete random variances and its practical implications.