EXPLANATION OF PROCEDURE USED WITH Z-TABLE NUMBER 1.

Z-TABLE NUMBER 1 includes all z-score entries. In addition, it provides the area to the left of the z-score that includes the total population.

You want to get the proportion of the population that has a z-score less than 2 so you enter a z-score of 2. The z-table entry is .977250 (top left picture).

You want to get the proportion of the population that has a z-score less than -2 so you enter a z-score of -2. The z-table entry is .022750 (top middle picture).

You want to get the proportion of the population that has a z-score entry greater than 2. You enter a z-score of 2. The z-table entry is .977250. This is the area to the left of the z-score. You want the area to the right of the z-score. You subtract .977250 from 1 to get .022750 (top right picture).

You want to get the proportion of the population that has a z-score entry greater than -2 and less than 2. You take the area to the left of a z-score of -2 (top middle picture) and you add it to the area to the right of a z-score of 2 (top right picture) and you subtract the sum from 1 to get 1 - .0455 = .9545 which is the area under the distribution curve that is BETWEEN -2 and 2 (bottom left picture).

You want to get the proportion of the population that has a z-score entry less than -2 or greater than 2. You take the area to the left of a z-score of -2 (top middle picture) and you add it to the area to the right of a z-score of 2 (top right picture) to get .0455 which is the area under the distribution curve that is OUTSIDE z-score entries of -2 and 2 (bottom right picture).