Question

Find the value of z such that 0.96420.9642 of the area lies between −z−z and z. round your answer to two decimal places.

Answer 1

If z represents the variable of the standard normal distribution curve N(0,1), which is symmetrical about z=0, then we look for
P(z)-P(-z)=0.9642=1-2P(-z) => P(-z)=(1-0.9642)/2=0.0179
=>
-z=-2.099192
=> z=2.099192
Check:
P(2.099192)-P(-2.099192)=0.9642 ok