Z-Score Percentiles

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-Score = (X - μ) / σ, where X is the value, μ is the mean, and σ is the standard deviation.

Front

What does a Z-Score of 0 indicate?

Back

A Z-Score of 0 indicates that the data point is exactly at the mean.

Front

What does a positive Z-Score indicate?

Back

A positive Z-Score indicates that the data point is above the mean.

Front

What does a negative Z-Score indicate?

Back

A negative Z-Score indicates that the data point is below the mean.

Front

What is the empirical rule in statistics?

Back

The empirical rule states that for a normal distribution, approximately 68% of the data falls within one standard deviation of the mean, 95% within two standard deviations, and 99.7% within three standard deviations.

Front

What is a percentile?

Back

A percentile is a measure used to indicate the value below which a given percentage of observations in a group of observations falls.

Front

How do you find the percentile rank of a score?

Back

Percentile Rank = (Number of values below X / Total number of values) * 100.

Front

What is the 50th percentile also known as?

Back

The 50th percentile is also known as the median.

Front

What is the significance of the 95th percentile?

Back

The 95th percentile indicates that 95% of the data points fall below this value.