The mean diastolic blood pressure for a random sample of 90

The mean diastolic blood pressure for a random sample of 90 people was 92 millimeters of mercury. If the standard deviation of individual blood pressure readings is known to be 12 millimeters of mercury, find a 95% confidence interval for the true mean diastolic blood pressure of all people. Then complete the table below. What is the lower limit of the 95% CI? What is the upper limit of the 95% CI?