Standard Deviation and Normal Distribution Flashcard

Front

What is standard deviation?

Back

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

Front

What does a z-score represent?

Back

A z-score indicates how many standard deviations an element is from the mean.

Front

If a score is below the mean, what will its z-score be?

Back

The z-score will be negative.

Front

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

Back

Approximately 68% of the data falls within one standard deviation of the mean.

Front

What is the mean in a data set?

Back

The mean is the average of all the numbers in the data set.

Front

How do you calculate the standard deviation?

Back

1. Find the mean. 2. Subtract the mean from each data point and square the result. 3. Find the average of those squared differences. 4. Take the square root of that average.

Front

What does it mean if the standard deviation is low?

Back

A low standard deviation indicates that the data points tend to be close to the mean.

Front

What does it mean if the standard deviation is high?

Back

A high standard deviation indicates that the data points are spread out over a wider range of values.

Front

In a normal distribution, what shape does the graph take?

Back

The graph of a normal distribution is bell-shaped.

Front

What is the empirical rule?

Back

The empirical rule states that for a normal distribution: 68% of data falls within 1 standard deviation, 95% within 2, and 99.7% within 3.