document.write( "Question 1197760: Old Faithful geyser in Yellowstone National Park has a mean time between eruptions of 85 minutes. If the interval of time between eruptions follows a normal distribution with standard deviation 21.25 minutes, what is the probability that a random sample of 32 time intervals between eruptions has a mean longer than 87 minutes? Include four digits after the decimal. \n" ); document.write( "

Algebra.Com's Answer #831162 by ewatrrr(24785) $\"\"$ $\"About$

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document.write( "Hi  \r\n" );
document.write( "Normal Distribution: µ = 85 and σ = 21.25\r\n" );
document.write( "n = 32  (NOte:  Sample Size > 30)\r\n" );
document.write( "Using TI or similarly an inexpensive calculator like an Casio fx-115 ES plus\r\n" );
document.write( "P(x > 87) =  normcdf( 87, 9999,  85, 21.25/√32) =\r\n" );
document.write( "Or\r\n" );
document.write( " =  = .5324\r\n" );
document.write( " 1- P( z ≤.5324) = 1- .7027 = \r\n" );
document.write( "    \r\n" );
document.write( "Wish You the Best in your Studies.\r\n" );
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