Answer:
The percentage of adult female reaction times that lie between 140.5 and 648.1 milliseconds is 99.7%.
Step-by-step explanation:
The Empirical Rule states that, for a normally distributed random variable:
68% of the measures are within 1 standard deviation of the mean.
95% of the measures are within 2 standard deviation of the mean.
99.7% of the measures are within 3 standard deviations of the mean.
In this problem, we have that:
Mean = 394.3 ms
Standard deviation = 84.6 ms
Use the Empirical Rule to determine the approximate percentage of adult female reaction times that lie between 140.5 and 648.1 milliseconds.
140.5 = 394.3 - 3*84.6
So 140.5 is 3 standard deviations below the mean.
648.1 = 394.3 + 3*84.6
So 648.1 is 3 standard deviations above the mean.
By the Empirical Rule,
The percentage of adult female reaction times that lie between 140.5 and 648.1 milliseconds is 99.7%.
