document.write( "Question 872649: The purchases made by customers at a convenience store are normally distributed, with a mean of $8.50 and a standard deviation of $6.00. What is the probability that a randomly chosen customer makes a purchase between $2.50 and $14.50?\r
\n" ); document.write( "\n" ); document.write( "Thank you very much! \n" ); document.write( "
Algebra.Com's Answer #526366 by ewatrrr(24785)\"\" \"About 
You can put this solution on YOUR website!

\n" );
document.write( "Hi
\n" );
document.write( "mean of $8.50 and a >standard deviation of $6.00
\n" );
document.write( "P($2.50 ≤ x ≤ $14.50) = P(-1 ≤ z ≤ 1) = .8413 -.1587 = .6826  0r 68.26%\r
\n" );
document.write( "\n" );
document.write( "For the normal distribution: 
\n" );
document.write( "one  standard deviation from the mean accounts for about 68% of the set 
\n" );
document.write( "two standard deviations from the mean account for about 95%
\n" );
document.write( "and three standard deviations from the mean account for about 99.7%.\r
\n" );
document.write( "\n" );
document.write( "Important to Understand z -values as they relate to the Standard Normal curve:
\n" );
document.write( "Below:  z = 0, z = ± 1, z= ±2 , z= ±3 are plotted.  
\n" );
document.write( "Note: z = 0 (where the x-value is the mean)
\n" );
document.write( " 50% of the area under the curve is to the left and %50 to the right
\n" );
document.write( "\r
\n" );
document.write( "\n" );
document.write( " \n" );
document.write( "
\n" );