A pharmaceutical company wants to study the effectiveness of three different versions of a drug that treats depression.  The company refers to these versions as A, B and C.  A clinical study whereby patients are treated using one of the three versions is administered.  Data on drug effectiveness, age, and the version of the drug taken are collected for 36 patients.  Data for the first 10 patients are shown below.  The company wants to know whether the three versions of the drug equal in their effectiveness, and whether age influences the effectiveness of these three versions of the drug. Accordingly, multiple regression analysis is performed for effectiveness (Y) against age, drug version and possible interactions
1.         How is Drug C being represented in the regression model?  Did the analyst forget to include it in the model?

 
 
 2.         How good is the regression model?  Please comment on the appropriate Regression Statistics (shown in the output) in answering this question.
 
 
3.         From the regression model, determine and interpret the coefficient for age for a patient who takes Drug A.
 
 
 
 
 
4.         Are the interactions captured in the regression analysis statistically significant?
 
 
 
 
 
5.         Use the regression equation to make following predictions:
 
What is the predicted drug effectiveness for a 40 years old patient who takes Drug A ________
 
 
 
 
What is the predicted drug effectiveness for a 65 years old patient who takes Drug A ________
 
 
 
 
What is the predicted drug effectiveness for a 40 years old patient who takes Drug B ________
 
 
 
 
What is the predicted drug effectiveness for a 65 years old patient who takes Drug B ________
 
 
 
 
What is the predicted drug effectiveness for a 40 years old patient who takes Drug C ________
 
 
 
 
What is the predicted drug effectiveness for a 65 years old patient who takes Drug C ________