3 Written Questions

1. Loss of respondents to treatment or to measurement can produce artifactual effects if that loss is systematically correlated with conditions .
2. The impact of a threat can be added to that of another threat or may depend on the level of another threat.
3. The nature of a measure may change over time or conditions in a way that could be confused with a treatment effect.

3 Multiple Choice Questions

1. When units are selected for their extreme scores, they will often have less extreme scores on other variables, an occurrence that can be confused with a treatment effect.
   1. Regression
   2. Maturation
   3. Attrition
   4. Selection
2. Events occurring concurrently with treatment could cause the observed effect.
   1. Selection
   2. History
   3. Attrition
   4. Testing
3. Naturally occuring changes over time could be confused with a treatment effect.
   1. Maturation
   2. Selection
   3. Attrition
   4. Regression

3 True/False Questions

1. Testing → Events occurring concurrently with treatment could cause the observed effect.

   True        False

2. Selection → Systematic differences over conditions in respondent characteristics that could also cause the observed effect.

   True        False

3. Ambiguous Temporal Precedence → Lack of Clarity about which variable occurred first may yield confusion about which variable is the cause and which is the effect.

   True        False