The purpose of a study was to determine the effectiveness of two ...

[Kikoku]

The purpose of a study was to determine the effectiveness of two different analgesic agents in controlling pain during menstruation in females ages 18 to 21 years. Researchers administer a self-reported pain scale on days 2 and 3 of the menses.
 
  You infer that this procedure is an example of which of the following? A) Test-retest reliability
  B) Random sampling procedures
  C) Internal validity of the study
  D) Construct validation

Question 2

In an experimental design, the most serious threat to internal validity typically is:
 
  A) Mortality
  B) Selection
  C) Maturation
  D) History

[briseldagonzales]

Answer to Question 1

A
Feedback:
The stability of an instrument is the degree to which similar results are obtained on separate occasions. Stability is assessed through testretest reliability procedures. Researchers administer the measure to the same sample twice and then compare the scores. The self-reported pain scale administered on two different occasions is an example of testretest reliability, not of random sampling procedures or construct validation. The internal validity of the study is not being measured.

Answer to Question 2

A

[Kikoku]

Wow, this really help

[yeungji]

Excellent