How to Read the Table in Appendix B The entries in Appendix B give the area
under the standard normal curve between zero and a positive value ofz. Sup-
pose that we are interested in the area betweenz¼0 andz¼ 1 :35 (numbers are
first rounded o¤ to two decimal places). To do this, first find the row marked
with 1.3 in the left-hand column of the table, and then find the column marked
with .05 in the top row of the table (1: 35 ¼ 1 : 30 þ 0 :05). Then looking in the
body of the table, we find that the ‘‘1.30 row’’ and the ‘‘.05 column’’ intersect at
the value .4115. This number, 0.4115, is the desired area betweenz¼0 and
z¼ 1 :35. A portion of Appendix B relating to these steps is shown in Table 3.8.
Another example: The area betweenz¼0 andz¼ 1 :23 is 0.3907; this value is
found at the intersection of the ‘‘1.2 row’’ and the ‘‘.03 column’’ of the table.
Inversely, given the area between zero and some positive valuez, we can find
that value ofz. Suppose that we are interested in azvalue such that the area
between zero andzis 0.20. To find thiszvalue, we look into the body of the
table to find the tabulated area value nearest to 0.20, which is .2019. This
number is found at the intersection of the ‘‘.5 row’’ and the ‘‘.03 column.’’
Therefore, the desiredzvalue is 0.53ð 0 : 53 ¼ 0 : 50 þ 0 : 03 Þ.
Figure 3.5 Area under the standard normal curve as in Appendix B.TABLE 3.8
z .00 .01 .02 .03 .04 .05 etc...
.0
.1
.2
...??
?
??
?
y1.3 ! : 4115
...
NORMAL DISTRIBUTION 125