Normal Probability Distributions Graph

Which is NOT true about the normal distribution curve?

• It is bell-shaped.

• The mean, median, and mode are approximately equal

• The smaller the standard deviation, the less spread in the curve.

• It is asymmetrical.

In a factory, the weight of the concrete poured into a mold by a machine follows a normal distribution with a mean of 1150 pounds and a standard deviation of 22 pounds. Approximately 95% of molds filled by this machine will hold weights in what interval?

• 1084 to 1216 pounds 

• 1106 to 1150 pounds 

• 1106 to 1194 pounds 

• 1128 to 1172 pounds

At a local high school, GPA's are normally distributed with a mean of 2.9 and standard deviation of 0.6. What percentage of students at the high school have a GPA between 2.3 and 3.5?

• 68%

• 99.7%

• 95%

• 84%

The shelf life of a particular dairy product is normally distributed with a mean of 12 days and a standard deviation of 3 days.

About what percent of the products last between 12 and 15 days?

• 68%

• 34%

• 16%

• 2.5%

Use the following information and the Empirical Rule to estimate the answer.

The ages of golfers are normally distributed, with a mean of 38 and a standard deviation of 4.

Find the percentage of golfers that are between 30 and 46 years old.

• 68%

• 94%

• 95%

• 99.7%

Use the following information and the Empirical Rule to estimate the answer.

The ages of golfers are normally distributed, with a mean of 38 and a standard deviation of 4.

Find the proportion of golfers that are older than 42.

• 13.5%

• 16%

• 50%

• 85%

Use the following information and the Empirical Rule to estimate the answer.

The ages of golfers are normally distributed, with a mean of 38 and a standard deviation of 4.

There are 500 golf members at the Mathy Country Club. How many are younger than 34?

• 16

• 80

• 100

• 150

A 12 oz can of soda has a mean volume of 12 oz, with a standard deviation of .25 oz. How common are cans with less than 11.5 oz of soda? Calculate the probability.

• 2.5%

• 0.15%

• 2.35%

• 2.25%

The mean life of a tire is 30 000 km. The standard deviation is 2000 km. 68% of all tires will have a life between ______km and ______km.

• 26000 and 34000

• 28000 and 32000

• 24000 and 34000

• 22000 and 36000

What shape is a normal distribution curve?

• Half curve

• Round curve

• Bell curve

• Square curve