Probabilities with the Normal Distribution

Find the value for 
P(Z > 1.78)

• 0.0376

• 0.0375

• 0.0446

• 0.2420

Find the value for 
P(Z < -0.39)

• 0.3498

• 0.3483

• 0.3501

• 0.6502

Find the value for
P(Z > 2.46)

• 0.00714

• 0.99305

• 0.00695

• 0.99286

Find the value for
P( -2.01 < Z < 0.88)

• 0.7884

• 0.2116

• 0.0222

• 0.1984

A continuous random variable is normally distributed with mean 145 and standard deviation is 5. Find P(136<X<140).

• 0.8054

• 0.8772

• 0.1228

• 0.1587

This data is normally distributed.  What percent of the data is in the shaded region?

• 68%

• 95%

• 99.7%

• 50%

Abigail is analyzing the test scores of her class, which are normally distributed. What percent of the scores fall within the shaded region?

• 68%

• 95%

• 99.7%

• 50%

This data is normally distributed. If this histogram represents data from 500 people, HOW MANY people are within two standard deviations of the mean?

• 499

• 475

• 340

• 47500

Answer explanation

In a normal distribution, approximately 95% of the data falls within two standard deviations of the mean. For 500 people, this means about 475 people are within this range, making 475 the correct answer.

What's the probability of 49 < x < 51 ? (Mean = 50, Standard dev = 6.5)

• 0.1192

• 0.1251

• 0.1587

• 0.0875

This data is normally distributed.  What percent of the data is in the shaded region?

• 68%

• 95%

• 99.7%

• 50%