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This question involves a series of questions involving gas prices.
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It says we're told that in the united states, gas prices follow normal distribution with a mean of 3 .76 and a standard deviation of 0 .25.
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And in russia, we're told that gas prices also follow an approximately normal distribution with mean 3 .39 and standard deviation of 0 .20.
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So the first thing we want to know is what is the probability that.
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In the u .s.
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We're being charged less than $3 .50.
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And we're going to round this to four decimals.
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So if we look at a normal distribution, 376 is in our middle, 350 is over here, and we're finding the area to the left of that.
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So the probability that x is less than 350.
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So using our graphing calculators, we're going to use our normal cdf.
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Our lower bound is negative 99999.
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Our upper bound is 350.
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Our mean is 3 .76.
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And our standard deviation is 0 .25.
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That tells us that the probability that it is less than $3 .50 is 0 .1492.
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Part b said what percent of gas in russia is more than 350.
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So we know the probability that x is greater than 350, but this is for russia...