z-score practice

Front

What is a z-score?

Back

A z-score indicates how many standard deviations an element is from the mean. It is calculated as (X - μ) / σ, where X is the value, μ is the mean, and σ is the standard deviation.

Front

How do you calculate a z-score?

Back

To calculate a z-score, use the formula: 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

If the mean waist size is 29 inches and the standard deviation is 2 inches, what is the z-score for a waist size of 33 inches?

Back

The z-score is 2.

Front

If the mean height of 3rd graders is 52 inches and the standard deviation is 2.5 inches, what is the z-score for a height of 47 inches?

Back

The z-score is -2.

Front

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

Back

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

Front

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

Back

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

Front

If a dairy product has a mean shelf life of 12 days and a standard deviation of 3 days, what percent of products last 6 days or less?

Back

About 2.5% of the products last 6 days or less.

Front

If a dairy product has a mean shelf life of 12 days and a standard deviation of 3 days, what percent of products last between 12 and 15 days?

Back

About 34% of the products last between 12 and 15 days.