Normal Distribution

Front

What is a Normal Distribution?

Back

A Normal Distribution is a probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean.

Front

What is the Empirical Rule?

Back

The Empirical Rule states that for a normal distribution: about 68% of the data falls within 1 standard deviation of the mean, about 95% falls within 2 standard deviations, and about 99.7% falls within 3 standard deviations.

Front

What percentage of data falls within 1 standard deviation of the mean in a normal distribution?

Back

68%.

Front

What percentage of data falls within 2 standard deviations of the mean in a normal distribution?

Back

95%.

Front

What percentage of data falls within 3 standard deviations of the mean in a normal distribution?

Back

99.7%.

Front

If the mean age of golfers is 38 and the standard deviation is 4, what is the age range for 68% of golfers?

Back

34 to 42 years old.

Front

If the mean height of adult American men is 69 inches and the standard deviation is 2.5 inches, what height range includes approximately 95% of men?

Back

64 inches to 74 inches.

Front

What is the mean in a normal distribution?

Back

The mean is the average of all data points and is the center of the normal distribution.

Front

What is the standard deviation in a normal distribution?

Back

The standard deviation measures the amount of variation or dispersion of a set of values.

Front

If the mean shelf life of a dairy product is 12 days with a standard deviation of 3 days, what percentage of products last between 12 and 15 days?

Back

34%.