z-scores and raw data

Front

What is a z-score?

Back

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

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 positive z-score indicate?

Back

A positive z-score indicates that the value is above the mean.

Front

What does a negative z-score indicate?

Back

A negative z-score indicates that the value is below the mean.

Front

If a student's z-score is 0, what does that mean?

Back

It means the student's score is exactly at the mean.

Front

What is the mean in a data set?

Back

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

Front

What is the standard deviation?

Back

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

Front

If the mean is 50 and the standard deviation is 10, what is the z-score for a value of 70?

Back

Z-score = (70 - 50) / 10 = 2.

Front

What does a z-score of +2.0 signify?

Back

It signifies that the value is 2 standard deviations above the mean.

Front

What does a z-score of -1.5 signify?

Back

It signifies that the value is 1.5 standard deviations below the mean.