The blood pressure (average of systolic and diastolic measurements) of each of 38 persons were measured.58 The

Question:

The blood pressure (average of systolic and diastolic measurements) of each of 38 persons were measured.58 The average was 94.5 (mm Hg). A histogram of the data is shown.

Which of the following is an approximate 95% confidence interval for the population mean blood pressure? Explain.
(i) 94.5 ± 16
(ii) 94.5 ± 8
(iii) 94.5 ± 2.6
(iv) 94.5 ± 1.3