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This problem says the patient recovery time from a particular surgical procedure is normally distributed with a mean of four days and a standard deviation of two days.
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Let x be the recovery time for a randomly selected patient.
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Round all answers to four decimal places where possible.
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And we're asked two questions.
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First, the probability of spending between 4 .7 and 5 .4 days in recovery.
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And we also want to know the 90th percentile for recovery time and the number of days.
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And since we're told this is a normal distribution, we can find the probability that we lie between 4 .7 and 5 .4 days for our random observation with normal cdf in our calculator.
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And for normal cdf, you start off with your two values you want the probability between, or your lower bound and upper bound, which in our case is 4 .7, followed by 5 .4.
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And then we use the mean and standard deviation of our normal distribution.
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In our case, that's four, and then two for the standard deviation...