Vanessa and Jenny take a reaction-time test.Vanessa's reaction time is 0.23 seconds,and Jenny's reaction time is 0.25 seconds.Suppose that the stopwatch the psychologist used only measured to a tenth of a second.The psychologist concludes that Vanessa and Jenny have equal reaction times of 0.2 seconds.As a measure of reaction time,the stopwatch lacks:
A)reliability.
B)validity.
C)power.
D)reactivity.

Question

Quizplus · Accepted Answer

The stopwatch lacks power because it cannot measure differences smaller than a tenth of a second, thus failing to distinguish between Vanessa's and Jenny's reaction times accurately.

Vanessa and Jenny Take a Reaction-Time Test