Standard Normal Probabilities

The volumes of soda in quart soda bottles can be described by a Normal model with a mean of 32.3 oz and a standard deviation of 1.2 oz. What percentage of bottles can we expect to have a volume less than 32 oz?

• 0.4013

• 0.2403

• 0.5204

• 0.1407

A town's average snowfall is 48 inches per year with a standard deviation of 6 inches. Using a Normal model, what percent of snowfall amounts will be between 40 and 50?

• 0.5393

• 0.4607

• 0.3719

• 0.7234

In Standford, CA, cars were traveling at a mean speed of 23.84 mph, with a standard deviation of 3.56 mph. One car's z-score was +3.2. How fast was that car going?

• 72.728 mph

• 12.448 mph

• 35.232 mph

• 32.563 mph

Answer explanation

A town has a speed limit of 45 mph. If the speeds of cars traveling in the town can be described by a Normal model with a mean of 48 mph and a standard deviation of 3.5 mph, what percent of cars are exceeding the speed limit?

• 80.43%

• 19.56%

• 23.86%

• 75%

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

• 68%

• 95%

• 50%

• 99.7%

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

• 68.

• 95%

• 99.7%

• 50%

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

• 5%

• 95%

• 2.5%

• 50%

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

• 5%

• 95%

• 2.5%

• 50%

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

• 68%

• 32%

• 95%

• 50%

The area under a standard normal curve to the right of a particular z-value is 0.50. Which of the following describes the z-value?

• Positive

• Negative

• Zero

• Unknown