Researchers compared college students who reported they had ...

[javeds]

Researchers compared college students who reported they had smoked marijuana at least fifteen days a month with similar students who said they smoked five days a month at most. A day after going without marijuana, the heavy users performed significantly worse on tasks that involved sustaining and shifting attention. The research design is
 
  a. single-group.
  b. time-series.
  c. before-after.
  d. comparison-group.

Question 2

An experimenter is interested in the influence of taking a one-semester-long test preparation course on performance on the Scholastic Aptitude Test (SAT). She contacts high school students who have and who have not taken the course and compares their scores on the SAT exam. She finds that the students who have taken the course score significantly higher on the test. The research design is
 
  a. comparison-group before-after.
  b. single-group before-after.
  c. comparison-group.
  d. experimental.

[coyin]

Answer to Question 1

d

Answer to Question 2

c

[javeds]

TYSM

[xoxo123]

Thanks for the timely response, appreciate it