A Nursing Professor Wishes to Determine If There Is an Association

Multiple Choice

A nursing professor wishes to determine if there is an association between her students grades and three independent variables (use of online tutorials, the use of quiz review sessions and participation in study sessions) . When she adds the third variable the standard error of the estimate changes from 8.2 to 9.4. She knows this means:

A) She should include all the independent variables in her model because they are all important.
B) She is unable to determine what the change means without an R squared value.
C) There is a clinically significant relationship between the use of resources and final grades.
D) The prediction made by the model including the three variables will be less accurate.