Question 924488
mean = 73, sd = 11.35, {{{z = blue(x - 73)/blue(11.35)}}}    
Using the z-value to determine the Probability:
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And...Using a TI calculator 0r similarly a Casio fx-115 ES plus
P( x < 100) = P( z < 27/11.35) = P( z < 2.3788) = normalcdf(-100, 2.3788) = .9913
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For the normal distribution: Below:  z = 0, z = ± 1, z= ±2 , z= ±3 are plotted.  
<u>Area under the standard normal curve to the left of the particular z</u> is P(z < than its value)
Note: z = 0 (x value: the mean) 50% of the area under the curve is to the left and 50%  to the right
{{{drawing(400,200,-5,5,-.5,1.5, graph(400,200,-5,5,-.5,1.5, exp(-x^2/2)), green(line(1,0,1,exp(-1^2/2)),line(-1,0,-1,exp(-1^2/2))),green(line(2,0,2,exp(-2^2/2)),line(-2,0,-2,exp(-2^2/2))),green(line(3,0,3,exp(-3^2/2)),line(-3,0,-3,exp(-3^2/2))),green(line( 0,0, 0,exp(0^2/2))),locate(4.8,-.01,z),locate(4.8,.2,z))}}}