Question

At a fixed operating setting, the pressure in a line downstream of a reciprocating compressor is known to maintain a mean value of 12.0 bar with a standard deviation of 1.0 bar based on its history. what is the probability that the line pressure will exceed 13.0 bar during any measurement?

Answer 1

Approximately 34% of a normal distribution is within 1 standard deviation above the mean. Your probability is about 100% - (50% +34%) = 16%.

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This is a number most statistics students are asked to memorize.