Assuming an approximately normal data set, find the 99.7% confidence interval for systolic blood pressure in women given a sample size of 1000 with a mean of 123.4 and a standard deviation of 19.9.
1.73.65 – 173.15 3.103.5 – 143.3
2.63.7 – 183.1 4.83.6 – 163.2
A 99.7% confidence interval translates to the area within 3 standard deviations of the mean. We know the standard deviation is 19.9. Now, just multiply that by 3 and you have 59.7.
Add and subtract that from the mean to find the interval.