The systolic blood pressure of 18-year-old women is normally distributed with a mean of 120 mmHg and a standard deviation of 12
mmHg. What percentage of 18-year-old women have a systolic blood pressure that lies within 3 standard deviations of the mean? (A) 68%
(B) 95%
(C) 100%
(D) 99.7%
We are asked to find the percentage of 18-year-old women that will have a systolic blood pressure that lies within 3 standard deviations of the mean.
The empirical rule of normal distribution states approximately 68% of data lies within one standard deviation of mean, approximately 95% of data lies within two standard deviations of mean and approximately 99.7% of data lies within three standard deviations of mean.
Since the systolic blood pressure of 18-year-old women is normally distributed, therefore, 99.7% of 18-year-old women have a systolic blood pressure that lies within 3 standard deviations of the mean.
