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This problem says the annual per capita consumption of bottled water was 33 .3 gallons.
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Assume that the per capita consumption of bottled water is approximately normally distributed with a mean of 33 .3 and a standard deviation of the 10 gallons.
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And we're asked four questions, and the first three questions are going to be done very similarly because we're asked for the probability that we're more than a value between two values or less than a value.
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And for all of those, since this is a normal distribution of the population, we can use normal cdf in our calculator.
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And for that operation, we need four things.
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The lower bound, the upper bound, followed by the mean or the average, and the standard deviation.
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And the mean and the average for all three of the first problems for a through c are going to be the same.
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We're going to have 33 .3 for the mean and then the standard deviation of 10.
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And that's going to stay the same for the last two blanks for each of our problems.
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And then the thing that's going to change is our lower and upper bound depending on our scenario.
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Here we want the probability that we're more than 38.
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More than 38 means we're at 38 or greater in the curve, so our lower bound would be 38.
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And we'll use infinity to make sure we cover everything in the normal curve to the right.
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And when we enter in this normal cdf operation in the calculator, the answer we get, rounded to four decimal places like the directions ask, is 0 .3192...