Normal Probability Distributions

What is the the total probability under the normal distribution curve?

• 10%

• 25%

• .5%

• 100%

Between what two standard deviations of a normal distribution lies 68% of the data?

• one below and one above

• two below and two above

• two below and zero

• zero and two above

Between what two standard deviations of a normal distribution lies 95% of the data?

• one below and one above

• two below and two above

• two below and zero

• zero and two above

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

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

• 68%

• 32%

• 16%

• 50%

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

• 5%

• 95%

• 2.5%

• 50%

In an Oreo factory, the mean mass of a cookie is given as 40 g. For quality control, the standard deviation is 2 g. If 10 000 cookies were produced, how many cookies are within 2 g of the mean?

• 6800

• 9500

• 3200

• 9750

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%

• 99.7%

• 95%

• 34%

Which set of exam data better represents a normal distribution?

• Exam 2

• Exam 1

• Neither

• Both

Which distribution has the smallest standard deviation?

• red

• yellow

• green

• blue

• they are all the same