Normal Distributions (Empirical Rule)

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%

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

• one below and one above
• two below and two above
• two below and zero
• zero and two above

What percentage of dogs weigh less than 58 pounds? Explain how you arrived at your answer.

(a)  

What percentage of dogs weigh between 34 and 58 pounds? Explain how you arrived at your answer.

(a)  

What percent of a normal distribution lies outside of ±3 standard deviations?

• 99.7%

• .15%

• .3%

• 100%

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%

Which interval shows 95% 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

The Empirical (68-95-99.7) Rule can be applied only if data is ....

• Normally Distributed

• Uniform

• Skewed

• Symmetric