Z-Scores & Z-tables

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 is the Z-score calculated?

Back

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 data set has a mean of 50 and a standard deviation of 10, what is the Z-score for a value of 60?

Back

Front

What is the purpose of a Z-table?

Back

A Z-table shows the percentage of values below a given Z-score in a standard normal distribution.

Front

What percentage of values lie within one standard deviation of the mean in a normal distribution?

Back

Approximately 68% of values lie within one standard deviation of the mean.

Front

What percentage of values lie within two standard deviations of the mean in a normal distribution?

Back

Approximately 95% of values lie within two standard deviations of the mean.

Front

What percentage of values lie within three standard deviations of the mean in a normal distribution?

Back

Approximately 99.7% of values lie within three standard deviations of the mean.

Front

If the mean is 100 and the standard deviation is 15, what is the Z-score for 85?

Back