Statistics 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 shape does a normal distribution curve have?

Back

Bell curve.

Front

What is the mean in a normal distribution?

Back

The mean is the average of all data points in a distribution.

Front

What is a standard deviation?

Back

Standard deviation is a measure of the amount of variation or dispersion in a set of values.

Front

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

Back

Approximately 68% of the data.

Front

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

Back

Approximately 95% of the data.

Front

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

Back

Approximately 99.7% of the data.

Front

If the mean is 75 and the standard deviation is 7, what is the z-score for a value of 82?

Back

Z-score = (82 - 75) / 7 = 1.

Front

What does a z-score represent?

Back

A z-score represents the number of standard deviations a data point is from the mean.

Front

In a normal distribution, what does the area under the curve represent?

Back

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