Vanessa and Jenny Take a Reaction-Time Test

Multiple Choice

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.