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 10 participants. The objective of the study is to assess how systolic blood pressure changes untreated overtime. Systolic blood pressures are measured at baseline and again 4 weeks later. Compute a 95% confidence interval for the mean difference in blood pressure over 4 weeks.
Baseline 120 145 130 160 152 143 126 121 115 135
4 weeks 122 142 135 158 155 140 130 120 124 130