1. A clinical trial is planned to compare an experimental medication designed to lower blood pressure to a

1.                  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 over time untreated.  Systolic blood pressures are measured at baseline and again 4 weeks later.  Compute a 95% confidence interval for the difference in blood pressures 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