Question

A clinical trial is planned to compare an experimental medication designed to lower blood pressure to a placebo. Before starting the trial, a pilot study is conducted involving seven participants. The objective of the study is to assess how systolic blood pressures change over time if left untreated. Systolic blood pressures are measured at baseline and 4 weeks later. Is there a statistically significant difference in blood pressures over time? Run the test at a 5% level of significance. baseline-120 145 130 160 152 143 126 4weeks-122 142 135 158 155 140 130 Make sure to do Problems 7.7 and 7.8 by hand. For all four problems, whether you do calculations by hand or they are done using SAS, make sure you answer the question using the 5-Step Process for Hypothesis Testing described in your textbook in Chapter 7.

Answer 1

Let D= 4 weeks - baseline

So the values of D are: 2,-3,5,-2,3,-3,4

So we have Mean of D= 0.857 and sample s.d of D= 3.4365

We are testing,

H0: Ud=0 vs H1:Ud not equal to 0

Under H0, test statistic= 0.857/(3.4365/√7) = 0.660

The p value of this two sided test is, 2P(t 6 >0.660) = 0.5338

Since the p-value is clearly greater than 0.05, we have insufficient evidence to Reject H0. So we cannot conclude that a significant difference is there in blood pressure over time at the 5% level.