Question 305698: A clinical trial is planned to compared an experimental mediciation 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 change untreated over time. Systolic blood pressure are mesaured at baseline and again 4 weeks later,
Computed 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
I'm looking for how it solves with 95% for calcuated, It makes confused me formula. using mean -( )*(sqrt/( )?
Gloria
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A clinical trial is planned to compared an experimental mediciation 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 change untreated over time. Systolic blood pressure are mesaured at baseline and again 4 weeks later,
Computed 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
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Difference:-2,3,-5,2,-3,3,1,-9,5
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mean of the differences: -0.5556
std of the differences: 4.5308
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Generate the 95% CI:
x-bar = -0.5556
standard error = ME = invT(0.975 with df = 8)*s/sqrt(n)
= 2.3060*4.5306/sqrt(9)
= 3.4825
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95% CI: -0.5556-3.4825 < u(diff) < -0.5556+3.4825
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Cheers,
Stan H.
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