Front

What is the Empirical (68-95-99.7) Rule?

Back

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

Front

What type of distribution does the Empirical Rule apply to?

Back

Normally Distributed.

Front

What is the mean of a normal distribution?

Back

The mean (μ) is the center of the curve and represents the average value of the data set.

Front

What does a standard deviation (σ) indicate in a normal distribution?

Back

Standard deviation measures the dispersion or spread of the data points around the mean.

Front

How do you calculate a z-score?

Back

Z-score = (X - μ) / σ, where X is the value, μ is the mean, and σ is the standard deviation.

Front

What does a z-score represent?

Back

A z-score indicates how many standard deviations a data point is from the mean.

Front

What percent of households discard between 10 and 12 pounds of paper if the mean is 9.43 pounds and standard deviation is 4.17 pounds?

Back

17.68%.

Front

What percent of households throw out fewer than 2 pounds of paper if the mean is 9.43 pounds and standard deviation is 4.17 pounds?

Back

3.74%.

Front

What is the purpose of z-scores?

Back

To describe the exact location of a score within a distribution.

Front

What does the area under the normal curve represent?

Back

The total area under the normal curve represents the total probability, which equals 1.