Question

Find the z value such that 39% of the standard normal curve lies between −z and z.

Answer 1

Value of Z =0.51

Explanation:

Given that P(-z<0<z) = 0.39

Or P(0<z) = 0.39/2 = 0.195

From standard normal table we find that

0.51 satisfies that

P(0<z<0.51) = 0.195

Hence value of z = 0.51

Answer 2

Use symmetry and find z so that probability is:
(100-39)/2
=61%
=30.5%~0.305
From the z-table:
z=-0.51
Answer: -0.51