Empirical Rule

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

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CCSS.HSS.ID.A.4

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%

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CCSS.HSS.ID.A.4

At a local high school, GPA's are normally distributed with a mean of 2.9 and standard deviation of 0.6. What is the GPA of the highest 2.5% of the students?

• 4.1 
• 4.1 or higher
• 4.7
• 4.5 or higher

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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.

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CCSS.HSS.ID.A.4

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%

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CCSS.HSS.ID.A.4

What percent of people are 3 standard deviations above the mean?

• .15

• 34

• 68

• 2.35

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CCSS.HSS.ID.A.4

What percent of people are 2 standard deviations or more above the mean?

• 2.35

• 34

• 68

• 2.5

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CCSS.HSS.ID.A.4

What percent of people within 1 standard deviation of the mean?

• 99.7

• 34

• 68

• 95

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CCSS.HSS.ID.A.4

What percent of people within 2 standard deviations of the mean?

• 99.7

• 34

• 68

• 95

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CCSS.HSS.ID.A.4

What percent of people within 3 standard deviations of the mean?

• 99.7

• 34

• 68

• 95

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CCSS.HSS.ID.A.4