Practice with 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 from the mean.

Front

How do you calculate a Z-score?

Back

Z = (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

What is the significance of a Z-score of 0?

Back

A Z-score of 0 indicates that the value is exactly equal to the mean.

Front

What percentage of data falls within 1 standard deviation of the mean in a normal distribution?

Back

Approximately 68% of the data falls within 1 standard deviation of the mean.

Front

What percentage of data falls within 2 standard deviations of the mean in a normal distribution?

Back

Approximately 95% of the data falls within 2 standard deviations of the mean.

Front

What is the 25th percentile also known as?

Back

The 25th percentile is also known as the 1st quartile.

Front

If a score has a Z-score of +2.00, what does it mean?

Back

It means the score is 2 standard deviations above the mean.

Front

If a score has a Z-score of -1.00, what does it mean?

Back

It means the score is 1 standard deviation below the mean.