Normal Distributions Probability

Which is NOT true about the normal distribution curve?

• It is bell-shaped.

• The mean, median, and mode are approximately equal

• The smaller the standard deviation, the less spread in the curve.

• It is asymmetrical.

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

• 25%

• 68%

• 95%

• 99.7%

Which of the following graphs shows a normal curve?

• 
• 
• 
• 

Where can we locate the mean in the normal curve?

• to the left portion

• to the right portion

• at the center

• on the z - axis

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.

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.

Find the proportion of golfers that are older than 42.

• 13.5%

• 16%

• 50%

• 85%

A 12 oz can of soda has a mean volume of 12 oz, with a standard deviation of .25 oz. How common are cans with less than 11.5 oz of soda? Calculate the probability.

• 2.5%

• 0.15%

• 2.35%

• 2.25%

The Empirical Rule's percents are:

• 68-95.7-99

• 68-95-99.7

• 68.7-95-99

Find the mean of the probability distribution.

• 85

• 83.2

• 87.1

• 84.4