In: Statistics and Probability
This is for Introduction to Probability and Statistics 14 ed. Chapter 13 Case Study pg. 572 "Made In the U.S.A." 4. what is the increase in R2 when you compare the fitted cubic with the fitted quadratic model?
The regession analysis is done in excel to see the difference in R square value between quadratic and cubic model. The qudratic model is define as,
The following steps were used in excel to perform the quadratic regression analysis,
Step1: Write the data values in excel. The screenshot is shown below,
Step 2: DATA > Data Analysis > Regression > OK. the screenshot is shown below,
Step 3: Insert Input Y Range: column Y, Input X Range: column X. The screenshot is shown below,
The result is obtained. The screenshot is shown below,
The R square value is,
Now the cubic regression equation id defined as,
The following steps were used in excel to perform the quadratic regression analysis,
Step1: Write the data values in excel. The screenshot is shown below,
Step 2: DATA > Data Analysis > Regression > OK. the screenshot is shown below,
Step 3: Insert Input Y Range: column Y, Input X Range: column X, X^2 and X^3. The screenshot is shown below,
The result is obtained. The screenshot is shown below,
The R square value is,
Now the difference in R square is,