Answer:
The interval that represents the middle 68% of her commute times is between 33.5 and 42.5 minutes.
Step-by-step explanation:
The Empirical Rule states that, for a normally distributed random variable:
Approximately 68% of the measures are within 1 standard deviation of the mean.
Approximately 95% of the measures are within 2 standard deviations of the mean.
Approximately 99.7% of the measures are within 3 standard deviations of the mean.
In this problem, we have that:
Mean of 38 minutes, standard deviation of 4.5 minutes.
Determine the interval that represents the middle 68% of her commute times.
Within 1 standard deviation of the mean. So
38 - 4.5 = 33.5 minutes
38 + 4.5 = 42.5 minutes.
The interval that represents the middle 68% of her commute times is between 33.5 and 42.5 minutes.
Square root it to cancel out the 2
In exact form it would be 15/8
