Correlation regression a If we are interested only in determining whether a relationship eXIStS, we use correlation analysis a If we are interested in predicting the value of one variable( the dependent variable)on the basis of other variables(the independent variables), we use Regression analysis a Dependent variable: denoted Y 口 ndependent variables: denoted x1X2…-Xk
11 Correlation & regression ◼ If we are interested only in determining whether a relationship exists, we use correlation analysis. ◼ If we are interested in predicting the value of one variable (the dependent variable) on the basis of other variables (the independent variables),we use Regression analysis . Dependent variable: denoted Y Independent variables: denoted X1, X2, …, Xk
Ex 1 Height of 2 vears old and 20 vears old Height of2yeas3930323435363630 old (inch) height of207163636768687064 years o (inch)
12 Ex.1 Height of 2 years old and 20 years old Height of 2 years old （inch） 39 30 32 34 35 36 36 30 height of 20 years old （inch） 71 63 63 67 68 68 70 64
Scatter plot 71 69 R67 岁65 63 30 32 34 36 38 40 X height of 2 years otd (inch)
13 Scatter plot Y height of 20 years old （inch ） X height of 2 years old（inch） 30 32 34 36 38 40 63 65 67 69 71
Correlation ■ Concept ■ Calculater Statistical inference for population correlation coefficient Hypothesis test
14 Correlation ◼Concept ◼Calculate r ◼Statistical inference for population correlation coefficient Hypothesis test