Question 930510
 the area under the standard normal curve that lies to the left of 
 Using a TI calculator 0r similarly a Casio fx-115 ES plus
.........
(a)z=1.02 = normalcdf(-100,1.02) = .8461  0r 84.61%
 (b)z=1.27 = normalcdf(-100,1.27)= .898
 (c)z=-0.86 = normalcdf(-100,-.86)= .195
 (d)z=-0.62 = normalcdf(-100,-.62)= .2676
..........
Recommend Using stattrek.com to check  Results
until You are familiar with Using Your Calculator.
Excel function: NORMSDIST (z) works as well.
...........
For the normal distribution: Below:  z = 0, z = ± 1, z= ±2 , z= ±3 are plotted.  
Area under the standard normal curve to the left of the particular z is P(z)
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))}}}