<PRE><B>Question 136094</B>
Assuming that the standard deviation of the population of systolic blood pressures of executives of major corporations is 26 mm Hg, what is the minimum sample size needed for the researcher to be 99% confident that his estimate is within 6 mm Hg of ? 
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z for 99% confidence = 2.5758..
Since E = 2.576*[26/sqrt(n)]
n = [2.576*(26/6)]^2
n= 124.605
n= 125 when rounded up
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Cheers,
Stan H.</PRE>