Find the value of z if the area under a standard normal curve (a) to the right of z is 0.3622; (b) to the left of z is 0.1131; (c) between 0 and z, with z > 0, is 0.4838; (d) between −z and z, with z > 0, is 0.9500.
Probability of x for an area under standard normal curve is given as follows: P(X)=P(z) a] when P(X≥x)=0.3622 The value of z will be: 1-0.3622=0.6378 The corresponding value in the z-table is: z=0.34
b] P(X≤x)=0.1131 The corresponding value in z-table is: z=-1.21
c] P(0≤X≤x)=0.4838 When P(x)=0 then z=0.5 P(x)=0.4838 then z=0.04 hence: Z=0.5+0.04=0.54
D] P(X≤x)=0.9500 the value of z>0 is z=1.66 Answer: z=1.66
