Percentiles and Z-Scores Practice

Front

What is a percentile?

Back

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

Front

How do you calculate the percentile rank of a data value?

Back

Percentile rank = (Number of values below the data value / Total number of values) x 100.

Front

What does the 87th percentile mean?

Back

It means that 87% of the data values fall below this value.

Front

What is a Z-score?

Back

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

Front

How is a Z-score calculated?

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 +2.00 indicate?

Back

It indicates that the score is 2 standard deviations above the mean.

Front

What does a negative Z-score signify?

Back

A negative Z-score indicates that the score is below the mean.

Front

If a data value has a Z-score of -1.02, what does this mean?

Back

It means the data value is 1.02 standard deviations below the mean.

Front

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

Back

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

Front

How do you interpret Adam's Z-score of +2.50?

Back

Adam scored 2.5 standard deviations above the average, indicating a high performance compared to peers.