Question 1150147
Probability a gym member spends less than 75 minutes at the gym:
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{{{(x- mean)/SD}}} = {{{(75 - 70)/20}}} = {{{5/20}}} = 0.25
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Look up 0.25 on a z-table.  The result is 0.5987.
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This means there is a 0.5987 probability a gym member spends less than 75 minutes at the gym.
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Probability a gym member spends less than 65 minutes at the gym:
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{{{(x- mean)/SD}}} = {{{(65 - 70)/20}}} = {{{(-5)/20}}} = -0.25
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Look up -0.25 on a z-table.  The result is 0.4013.
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This means there is a 0.4013 probability a gym member spends less than 65 minutes at the gym.
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So, the probability that a gym member spends between 65 and 75 minutes at the gym:
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{{{0.5987 - 0.4013}}} = 0.1974