Essential Statistics

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Chapter 9: The Normal Probability Distribution 389
Figure 9-29: Area and probability value for P(-2.32 ≤ z ≤ 1.91)
If we would like to use the standard normal tables, we may use the table
which gives an area between 0 and a specified -value. Since we need to
find P (-2.32   1.91), we will have to use an equivalent form to find the
probability. The equivalent form is the same as finding P(-2.32   0) +
P(0   1.91) = P(0   2.32) + P(0   1.91) = 0.4898 + 0.4719
= 0.9617. Note: Using the tables gives a slightly different answer. The
difference is 0.0001. This is shown in Figure 9-30. Of course, one could
have used the other tables to help solve.