Which factors would be considered threats to internal validity? ...

[MGLQZ]

Which factors would be considered threats to internal validity? (Select all that apply.)
 
  a. Time
  b. Selection effects
  c. History
  d. Testing
  e. Subject availability
  f. Cost
  g. Selection bias

Question 2

The nurse is critiquing a research study that used an experimental design. How can the nurse determine if the study's results are able to infer causality?
 
  a. The relationship between independent and dependent variables must be reciprocal.
  b. The relationship between independent and dependent variables must not be explainable by any other variable.
  c. Both independent and dependent variables should be characterized by reactive effects.
  d. Both independent and dependent variables should change as a result of the treatment.

[gstein359]

Answer to Question 1

ANS: C, D, G

Feedback
Correct History refers to events occurring outside the study setting that can affect the dependent variable.
Testing can affect the dependent variable because the effect of taking a pretest may affect the subjects' posttest performance (the dependent variable).
Selection bias occurs if precautions are not taken to obtain a representative sample. Randomly assigning subjects to groups helps to minimize selection bias.
Incorrect Time is a pragmatic consideration when determining the feasibility of a research question.
Selection effects occur when the researcher cannot attain the ideal sample population. This limits generalizability (external validity).
Subject availability is a pragmatic consideration when determining the feasibility of a research question.
Cost is a pragmatic consideration when determining the feasibility of a research question.

Answer to Question 2

ANS: B

Feedback
A The relationship between independent and dependent variables is not necessarily reciprocal.
B Critical to causality is the control of extraneous variables that may influence changes in the dependent variable.
C Reactive effects are the subjects' responses to being studied, which interfere with establishing a cause-and-effect relationship.
D In a cause-and-effect relationship, the independent variable changes the dependent variable.