Which threat to internal validity does the reversal time series ...

[big1devin]

Which threat to internal validity does the reversal time series design attempt to address?
 
  a. selection bias
  b. regression to the mean
   c. contemporary history
  d. pretest sensitization
  e. experimenter expectancy

Question 2

Contemporary history is a problem
 
  a. in all experimental and quasi-experimental designs
  b. when one group experiences an event that another group does not experience
  c. in research that deals with current events
   d. when another event occurs at the same time as the quasi-independent variable
  e. in program evaluation research

[soda0602]

Answer to Question 1

C

Answer to Question 2

D

[big1devin]

TYSM

[nothere]

Thanks for the timely response, appreciate it