Question

What are the five different ways the z-table can be used?

Answer 1

The five use of z table are:

(1)

Finding area left to any z-score. For example area left to z-score -1 is

P(z <-1) = 0.1587

(2)

Finding area right to any z-score. For example area left to z-score 1 is

P(z >1) = 1 - P(z <1) = 1 - 0.8413 =0.1587

(3)

Finding area between two z-scores. For example area between z-scores -1 and 1 is

P(-1 < z< 1) = P(z<1) - P(z < -1) = 0.8413 - 0.1587 = 0.6826

(4)

Finding z-score, let z, that has given area to its left. For example: for area 0.6736, z-score is 0.45.

(5)

Finding z-score,let z, that has given area to its right. For example: We need to find the z-score that has 0.3300 area to its right. So area left to z-score is 0.6700. For area 0.6700, z-score is 0.44. So area right to z-score 0.44 is 0.3300.