Z Scores and Normal Distribution

Front

What is a Z Score?

Back

A Z Score indicates how many standard deviations an element is from the mean of a distribution.

Front

What does a normal distribution look like?

Back

A normal distribution is a bell-shaped curve where most of the data points cluster around the mean.

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

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

Back

Approximately 99.7% of the data falls within three standard deviations of the mean.

Front

Define population in statistics.

Back

A population is the entire group of individuals or instances about whom we hope to learn.

Front

Define sample in statistics.

Back

A sample is a subset of the population used to represent the group.

Front

What is the purpose of using a sample?

Back

To make inferences about the population without surveying every individual.

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 negative Z Score indicate?

Back

A negative Z Score indicates that the value is below the mean.