8.2b Standard Normal Distribution Tables (Example 1)


8.2b Standard Normal Distribution Tables (Example 1)

Example 1:
Find the value of each of the following probabilities by reading the standard normal distribution tables.
(a) P(Z > 0.600)
(b) P(Z < –1.24)
(c) P(Z > –1.1)
(d) P(Z < 0.76)

Solution:
Standard Normal Distribution Table


*When reading the standard normal distribution tables, it involves subtraction of values.
(a)
From the standard normal distribution table, P(Z > 0.600) = 0.2743
(b)
P(Z < –1.24)
= P(Z > 1.24)
= Q(1.24)
= 0.1075 ← (reading from the standard normal distribution table)

(*In the standard normal distribution table, all the values of z are positive. As the curve is symmetrical about the vertical axis, the area of the shaded region in both of the graphs are the same.)


(c)
P(Z > –1.1)
= 1– Area P
= 1 – Q(–1.1)
= 1 – 0.1357 ← (reading from the standard normal distribution table)
= 0.8643
(d)
P(Z < 0.76)
= 1– Area P
= 1 – Q(0.76)
= 1 – 0.2236 ← (reading from the standard normal distribution table)
= 0.7764