Identify which one of the four types of
validity--measurement validity, statistical conclusion
validity, internal validity, or external validity—is violated in
each of the following scenarios.
Explain your decision.
1. In a study of circadian rhythms and response time to a
cognitive task, researchers ask study participants how many hours
they slept the night before in order to divide them into groups
based on sleepiness. They find that individuals who slept <7
hours do 2.0 times more poorly on cognitive tasks compared with
individuals who slept ≥7 hours (95% C.I. 1.05-3.53), and conclude
that sleepiness causes reduced cognitive ability.