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1、Simple linear regression,一、Concept and maths model: The simplest functional relationship of one variable to another in a population is the simple linear regression. X and Y model y=a+bx,independent variable,dependent variable,x,y,regression coefficient or slope,b,intercept,a,二、Basis thought 寻找一条最佳直
2、线反映x与y的线性依 存规律。,y x,Simple linear regression,Scatter plot,2.error question 第i个个体的误差为: i =(a+bx i )-yi 所有n 个个体的误差为: |i | i2=I 从而,所求直线 即使得I 为最小,b=Lxy /Lxx a=y-bx 求最小值点,Simple linear regression,Lxx -Recall the sum of squares of deviations from the mean,Lxy -Recall the sum of the cross products of devia
3、tions from the mean,Simple linear regression,三、 Basis method: method of least squares(最小二乘法),即 在线性回归分析中,估计模型的参数时,保证 the error sum of squares最小的原则。,Simple linear regression,四、Testing the Significance of a regression,1. t-Testing : tb=(b-0)/sb 其中,sb2=ss剩/((n-2)Lxx),v=n-2 residual ss剩= Lyy- b Lxy 2.coe
4、fficient of determination R2= regression ss回/total ss总 =b Lxy/Lyy 3. F-Testing : F= MS回/MS剩,五、Confidence intervals in regression 1. Confidence intervals for an Estimated y(预测): 已知自变量x去估计反应变量y。 (1) 的估计(条件平均值的100(1)%可信区 间 ):,Simple linear regression,(2)个体Y值的100(1)%容许区间:,Simple linear regression,2. prediction interval(预报): 已知反应变量y去估计自变量x。,Simple linear regression,Simple Linear Correlation,一、The correlation coefficient:,Simple linear Correlation,二、t-Testing:,Simple linear Correlation,