Fundamentals of Probability and Statistics for Engineers

68.3%

0.4

0.3

0.2

0.1

0

fX(x)

x

x

m

(a)

0.4

0.3

0.2

0.1

0

fX(x)

fX(x)

m

95.5%

(b)

0.4

0.3

0.2

0.1

0

m

(c)

x

99.7%

m–

m–2

m– 3

m+2

m + 3

m +

Figure 7. 7 The Area under the normal density function within the range (a) m , (b)
m 2 , and (c) m 3

204 Fundamentals of Probability and Statistics for Engineers

σ σ

σ σ

σ σ