Probabilities using Normal Distribution Tables

If the value we are looking for is smaller than the mean, the value of z is:

• Not enough information

• Negative

• Positive

• 0

If the value we are looking for is the same as the mean, the value of z is:

• Not enough information

• Positive

• Negative

• 0

What's the probability x < 13?

(Mean = 10, Variance = 4)

• 0.9332

• 0.2266

• 0.7734

• 0.0668

What's the probability x > 17?

(Mean = 15, Standard dev = 3)

• 0.7486

• 0.7454

• 0.2514

• 0.2546

What's the probability of the gray area?

(Mean = 55, Standard dev = 2.5)

• 0.8185

• 0.8413

• 0.8641

• 0.8389

What's the probability of x < 13 ?

(Mean = 20, Standard dev = 6.5)

• 0.1423

• 0.1401

• 0.0446

• 0.0359

What's the probability of the highlighted area?

(Mean = 30, Variance = 1)

• 0.8664

• 0.7863

• 0.9332

• 0.8754

What's the probability of the highlighted area?

(Mean = 100, Standard dev = 10)

• 0.9772

• 0.0228

• 0.1587

• 0.0062

What's the probability of 49 < x < 51 ?

(Mean = 50, Standard dev = 6.5)

• 0.1192

• 0.1251

• 0.1587

• 0.0875

If you had to guess the probability of the gray area, which would you choose?

• 0.2

• 0.4

• 0.6

• 0.8