总体回归函数.ppt

Relationships Between Quantitative Variables Chapter 5 Content Looking for Patterns with Scatter-plots Describing Linear Patterns with a Regression Line (Regression analysis) Measuring Strength and Direction with Correlation (correlation analysis) Why the Answers May Not Make Sense Correlation Does Not Prove Causation Key Terms Scatterplot散布图 Explanatory variable自变量 Response variable因变量 Dependent variable因变量 Y variable Y变量 X variable X变量 Positive association正相关 Linear relationship线性相关 Negative association负相关 Nonlinear relationship 非线性关系 Curvilinear relationship曲线关系 Outliers in regression回归分离物 Key Terms Regression analysis回归分析 Regression equation回归方程 Prediction预测 Regression line回归线 Slope of a straight line直线的斜率 intercept of a straight line直线的截距 Statistical relationship统计关系 Determination relationship确定关系 Predicted y预测Y值 Estimated y估计Y值 Extrapolation外推法 Prediction error预测误差 Key Terms Residual残差 Least squares最小平方 Least squares line最小平方线 SSE误差平方和 Sum of square errors (SSE)误差平方和 Correlation相关系数 Squared correlation (r2)相关系数平方 Proportion of variation explained by x 由X说明的变化部分 Sum of squares total (SSTO)总偏差平方和 Residual sum of squares残差平方和 Influential observation影响性观察 Causation versus correlation因果与相关 Three Tools we will use …p131 Scatterplot, a two-dimensional graph of data values Correlation, a statistic that measures the strength and direction of a linear relationship Regression equation, an equation that describes the average relationship between a response and explanatory variable 5.1 Looking for Patterns  with Scatterplots Questions to Ask about a Scatter-plot p132 What is the average pattern? Does it look like a straight line or is it curved? What is the direction of the pattern? How much do individual points vary from the average pattern? Are there any unusual data points? Example 5.1 Height and Hand-span p132 Data shown are the first 12 observations of a data set that includes the heights (in inches) and fully stretched handspans (in centimeters) of 167 co