Day 14: Z-scores

Front

What is a z-score?

Back

A z-score is a statistical measurement that describes a value's relationship to the mean of a group of values, expressed in terms of standard deviations.

Front

What does a positive z-score indicate?

Back

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

Front

What does a negative z-score indicate?

Back

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

Front

How do you calculate a z-score?

Back

Z-score = (X - Mean) / Standard Deviation, where X is the data value.

Front

What is the z-score for a data value that is exactly at the mean?

Back

The z-score is 0.

Front

Why are z-scores useful in statistics?

Back

Z-scores allow for comparison of data points from different distributions by standardizing them.

Front

If a z-score is +2, what does that mean?

Back

It means the data value is 2 standard deviations above the mean.

Front

If a z-score is -1.5, what does that mean?

Back

It means the data value is 1.5 standard deviations below the mean.

Front

What is the significance of a z-score of +1 or -1?

Back

A z-score of +1 indicates the value is above average, while -1 indicates it is below average.

Front

What is the relationship between z-scores and the normal distribution?

Back

In a normal distribution, z-scores can be used to determine the probability of a value occurring.