A certain group of tests subject had pulse rates with a mean of 77.1 beats per minute and standard deviation of 12.6 beats per minute. Would it be unusual for one of the test subjects to have a pulse rate of 82.3 beats per minute?
What is the minimum "usual" value equal beats per minute?
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This question requires a little bit of background in statistics. According to statistics, when data is represented using a standard bell-shaped curve (also known as a "Normal Distribution"), 68.2% of the data should fall within 1 standard deviation of the mean; 95.2% of the data should fall within 2 standard deviations of the mean; and 99.7% should fall within 3 standard deviations of the mean. Typically, anything beyond 2.5 or 3 standard deviations away from the mean would be considered "unusual." In this case, 82.3 beats per minute definitely falls within 1 standard deviation of the mean (77.1 ± 1SD = 77.1 ± 12.6 -->64.5-89.7), so I would consider 82.3 bpm to be a common pulse rate.
For a visual of this idea and for more information about normal distributions, visit http://www.mathsisfun.com/data/standard-normal-distribution.html.