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A student plans to conduct an expensive biological experiment measuring arterial

ID: 3131110 • Letter: A

Question

A student plans to conduct an expensive biological experiment measuring arterial flow rates. Because the experiment requires human patients, she needs to estimate the number of measurements required before conducting the experiment.

Based on previous experiments, she estimates that the flow measurements will be randomly distributed with a sample deviation of 1.8 ml/min. She plans to use an intravenous flow sensor with a guaranteed accuracy of 2 ml/min.

Estimate the minimum number of samples necessary to ensure that the random uncertainty is less than the bias uncertainty. Assume a 90% confidence level.

Explanation / Answer

The required sample size is as follows:

n=(2*zalpha/2*sigma/w)^2=(2*1.645*1.8/2)^2=8.76~9