Answer:
68%
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 75, standard deviation of 4.
What percent had scores between 67 and 75?
67 = 71 - 4
75 = 71 + 4
Within 1 standard deviation of the mean, so, by the Empirical Rule, 68%.
