Empirical Rule

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.

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

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

Which interval shows 99.7% 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

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

• 99.7%

• 0.3%

• 0.15%

• 50%

What is the percentage of data that falls within one standard deviation of the mean?

• 67%

• 65%

• 72%

• 68%

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

• 68%

• 95%

• 99.7%

• 50%

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

• 25%

• 68%

• 95%

• 99.7%

Which best describes the shaded part of this normal distribution graph?

• All data that is one or higher.

• All data that is one or more standard deviations above the mean.

• All data that is between 1 and 3.

• All data that is above the mean.

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

• 68%

• 95%

• 99.7%

• 50%