Empirical Rule

Front

What is the Empirical Rule?

Back

The Empirical Rule states that for a normal distribution, approximately 68% of the data falls within one standard deviation of the mean, about 95% falls within two standard deviations, and about 99.7% falls within three standard deviations.

Front

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

Back

Approximately 68%.

Front

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

Back

Approximately 95%.

Front

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

Back

Approximately 99.7%.

Front

If the mean weight of concrete is 1150 pounds and the standard deviation is 22 pounds, what is the interval for approximately 95% of the weights?

Back

1106 to 1194 pounds.

Front

If the mean life of a tire is 30,000 km and the standard deviation is 2000 km, what is the interval for 68% of the tires?

Back

28,000 km to 32,000 km.

Front

In a normal distribution, how do you calculate the interval for 99.7% of the data?

Back

Mean ± 3 standard deviations.

Front

What is the mean and standard deviation of GPA scores at a local high school?

Back

Mean: 2.9, Standard Deviation: 0.6.

Front

What is the interval for approximately 68% of students with GPAs between 2.3 and 3.5?

Back

2.3 to 3.5.

Front

If a normal distribution has a mean of 70 and a standard deviation of 5, what percent of scores are between 65 and 75?

Back

68%.