Question

Use a table of cumulative areas under the normal curve to find the​ z-score that corresponds to the given cumulative area. If the area is not in the​ table, use the entry closest to the area. If the area is halfway between two​ entries, use the​ z-score halfway between the corresponding​ z-scores. If​ convenient, use technology to find the​ z-score.

.048

Answer 1

Solution:

Given:

Area = 0.048

Use following Excel command:

=NORM.S.INV( probability)

=NORM.S.INV(0.048)

=-1.66456

=-1.665

Thus z value = -1.665

Using z table:

Look in z  table for Area = 0.048 or its closest area and find corresponding z value.

From above table we can see area 0.0480 is in between 0.0475 and 0.0485 and both are at same distance from 0.0480 , Hence corresponding z values are -1.66 and -1.67

Thus average of both z values is -1.665

Thus z  = -1.665.