What is the approximate area of the shaded region under the standard normal curve below? Use the portion of the standard normal table given to help answer the question. a. 0.02
b. 0.14
c.0.34
d.0.84

You want to find Pr[-2 < Z < -1].

The table tells you that

• Pr[Z < 0] = 0.5000

• Pr[Z < 1.00] = 0.8412

• Pr[Z < 2.00] = 0.9772

• Pr[Z < 3.00] = 0.9987

We have

Pr[-2 < Z < -1] = Pr[Z < -1] - Pr[Z < -2]

(because the distribution of Z is continuous)

… = Pr[Z > 1] - Pr[Z > 2]

(by symmetry of the distribution about its mean)

… = (1 - Pr[Z < 1]) - (1 - Pr[Z < 2])

(by definition of complement)

… = Pr[Z < 2] - Pr[Z < 1]

… = 0.9772 - 0.8412

… = 0.1360 ≈ 0.14 … … … (B)

d

step-by-step explanation: