It is appropriate to use dummy variables in multiple regression ...

[xclash]

It is appropriate to use dummy variables in multiple regression when
 
  a. there may be a nonlinear relationship between the independent variables and the dependent variable.
  b. all independent variables are interval or ratio.
  c. some of the independent variables are categorical.
  d. there may be nonnormality in the independent variables.

Question 2

A major reason for conducting correlational studies is to
 
  a. establish cause-and-effect relationships among variables.
  b. determine the effectiveness of various instructional methods.
  c. identify variables that have a substantial relationship with certain dependent variables.

[Harbringer]

Answer to Question 1

C

Answer to Question 2

C