document.write( "Question 1200611: Suppose the scores of students on an exam are Normally distributed with a mean of 488 and a standard deviation of 67. Then approximately 99.7% of the exam scores lie between the numbers
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document.write( " such that the mean is halfway between these two integers. \n" );
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Algebra.Com's Answer #834784 by Theo(13342) You can put this solution on YOUR website! mean is 488 and standard deviation is 67. \n" ); document.write( "99.7% of the exam scores lie between 289.162 and 686.838 \n" ); document.write( "critical z-score for two tailed confidence interval os .997 is equal to plus or minus 1.967737927. \n" ); document.write( "low z-score formula becomes -2.967737927 = (x - 488) / 67. \n" ); document.write( "solve for x to get x = 67 * -2.967737927 + 488 = 289.163 \n" ); document.write( "high z-score formula becomes 2.967737927 = (x - 488) / 67. \n" ); document.write( "solve for x to get x = 67 * 2.967737927 + 488 = 686.838. \n" ); document.write( "i did it the easy way by using the calculator at https://davidmlane.com/hyperstat/z_table.html \n" ); document.write( "here are the results from using that calculator. \n" ); document.write( " \r\n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |