Normal Distribution

What shape is a normal distribution curve?

• Half curve
• Round curve
• Bell curve
• Square curve

What is the the total area under the standard normal distribution curve?

• 100
• 25
• .5
• 1

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

• 25%
• 68%
• 95%
• 99.7%

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

• 25%
• 68%
• 95%
• 99.7%

What is the Normal Range (68%) of the annual precipitation for Phoenix, if the average is 29 with a standard deviation of 3?

• 26-32
• 3-29
• 26-29
• 39-32

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%

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.

The distribution of heights of adult American men is approximately Normal with mean 69 inches and standard deviation 2.5 inches. What percent of men are between 64 and 66.5 inches tall? 

• 50%
• 2.5%
• 13.5%
• 34%

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%

Find the Z-score.

Mean = 22

Standard Deviation: 3.1

x = 29

• 2.26

• 16.45

• -2.26

• 1.26