document.write( "Question 1195499: more normal distribution that i need help understanding. and learning how to use technology to help. thank you.\r
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document.write( "Suppose that Denver workers have a mean commute of 22 minutes and commute times are normally distributed with a standard deviation of 15 minutes. Let X represent the commute time for a randomly selected Denver worker.\r
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document.write( "Find the 85th percentile for the commute time of Denver workers. Round your answer to 1 decimal place.\r
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document.write( "The 85th percentile is minutes. \n" );
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Algebra.Com's Answer #828017 by Theo(13342)![]() ![]() You can put this solution on YOUR website! the mean is 22 minutes. \n" ); document.write( "the standard deviation is 15 minutes. \n" ); document.write( "85th percentile means that 85% have a commute time less than 22 minutes. \n" ); document.write( "this means that 15% have a commute time greater than 22 minutes. \n" ); document.write( "z-score is equal to (x - m) / s \n" ); document.write( "x is the raw score \n" ); document.write( "m is the mean \n" ); document.write( "s is the standard deviation, in this case. \n" ); document.write( "you are looking for a z-score that has 85% of all z-scores less than that. \n" ); document.write( "using a statistical calculator, you find that the z-score that has 85% of the commute time less than it would be equal to 1.03643338. \n" ); document.write( "use the z-score formula to find the raw score. \n" ); document.write( "z = (x - m) / s becomes 1.03643338 = (x - 22) / 15. \n" ); document.write( "solve for x to get: \n" ); document.write( "x = 15 * 1.03643338 + 22 = 37.5465007 minutes. \n" ); document.write( "that's the commute time that is in the 85th percentile, meaning that 85% of all commute times with a mean of 22 minutes and a standard deviation of 15 minutes will have a commute time less than that. \n" ); document.write( "you can use a z-score calculator online to confirm that. \n" ); document.write( "the online calculator that i used is at https://www.calculator.net/z-score-calculator.html \n" ); document.write( "the results from using that calculator are shown below: \n" ); document.write( " ![]() \n" ); document.write( "let me know if you have any questions. \n" ); document.write( "theo\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |