Question

A group of five individuals with high blood pressure were given a new drug that was designed to lower blood pressure. Systolic blood pressure was measured before and after treatment for each individual, with the following results:

Subject	Before	After
1	171	145
2	164	132
3	168	129
4	158	135
5	183	145

Let μXμX represent the population mean before treatment and let μYμY represent the population mean after treatment. Find a 90% confidence interval for the difference μD=μX−μYμD=μX−μY. Round the answers to three decimal places.

Answer 1

From the given data, values of d = Before - After are calculated as follows:

d = Before - After = 26, 32, 39, 23, 38

From d values, the following statistics are calculated:

n = Sample Size = 5

= Mean of d values = 31.6

sd = Standard deviation of d values = 7.092

SE = sd/

= 7,092/

= 3.1717

= 0.10

df = 5 - 1 = 4

From Table,

critical values of t = 2.132

Confidence Interval;

So,

Answer is:

(24.838, 38.362)