<PRE><B>Question 333211</B>
You are measuring the response of a new automobile braking system and are determining skid distance during panic braking. 
You are willing to accept an error of 2 feet. 
You choose to work at the 5% level of significance. 
From historical data, you know that the range of data for all skidding stops is about 24 feet 
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Since the range is 24 ft, 6*sigma = 24.
Therefore the standard deviation = 4
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Sample size = [z*s/E]^2 = [1.96*4/2]^2 = 15.36
Rounding up, n = 16.
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Cheers,
Stan H.</PRE>