Mechanical equipment sometimes needs to be calibrated so it ...

[jayhills49]

Mechanical equipment sometimes needs to be calibrated so it functions accurately. If a researcher fails to do this, data may suffer from low validity due to
 
  a. selection.
  b. instrumentation.
  c. statistical regression.
  d. history.

Question 2

Bray et al. (2001) studied alcohol use among sixth graders in the first year of their research, sixth and seventh graders in the second year, and six, seventh, and eighth grades in the third year.
 
  The design permitted separating age and cohort effects and the study is called a
  a. trend study.
  b. cohort study.
  c. cohort-sequential study.
  d. panel study.

[ghepp]

Answer to Question 1

B

Answer to Question 2

C

[jayhills49]

Thanks for the timely response, appreciate it

[mammy1697]

Gracias!