The Empirical Rule and Normal Distributions Practice

Elephants have the longest pregnancy of all mammals. One species of elephant has a mean gestation period of 525 days and a standard deviation of 32 days. The lengths of elephant pregnancies are approximately normally distributed. What percent of elephant pregnancies last less than 493 days?

• 68%

• 34%

• 16%

• 2.35%

Tags

CCSS.HSS.ID.A.4

What shape is a normal distribution curve?

• Half curve

• Round curve

• Bell curve

• Square curve

Which interval shows approx. 100% of the data given a mean of 15 and a standard deviation of 3?

• 9 to 21

• 12 to 18

• 6 to 24

• 13 to 16

Tags

CCSS.HSS.ID.A.4

According to the empirical rule, what percentage of data falls within 1 standard deviation? 

• 25%

• 68%

• 95%

• 99.7%

Tags

CCSS.HSS.ID.A.4

According to the empirical rule, how much of the data falls within 3 standard deviations? 

• 25%

• 68%

• 95%

• 99.7%

Tags

CCSS.HSS.ID.A.4

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

Tags

CCSS.HSS.ID.A.4

The mean life of a tire is 30,000 km. The standard deviation is 2000 km.

Then, 68% of all tires will have a life between ___________ km and __________ km.

•  28,000 km and 32,000 km.

• 24,000 km and 34,000 km.

• 26,000 km and 34,000 km.

• 27,000 km and 31,000 km.

Tags

CCSS.HSS.ID.A.4

Which of the following is a disadvantage of the Empirical Rule?

• There is no result for 3 standard deviations.

• It is very conservative.

• There is no result for 1 standard deviation.

• The data has to be approximately normal.

Tags

CCSS.HSS.ID.A.4

• Omega

• Delta

• Lowercase Sigma

• Lowercase Omega

Tags

CCSS.HSS.ID.A.4

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%

Tags

CCSS.HSS.ID.A.4