EOC Review ~ Statistics

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. It is calculated by subtracting the mean from the value and then dividing by the standard deviation.

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

Given a mean of 85 and a standard deviation of 2, what is the z-score for an observation of 82?

Back

Z-score = (82 - 85) / 2 = -1.5.

Front

What does a negative z-score indicate?

Back

A negative z-score indicates that the value is below the mean.

Front

What does a positive z-score indicate?

Back

A positive z-score indicates that the value is above the mean.

Front

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

Back

A z-score of 0 indicates that the value is exactly equal to 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 the difference between a population and a sample?

Back

A population includes all members of a specified group, while a sample is a subset of the population used to represent the group.

Front

What is standard deviation?

Back

Standard deviation is a measure of the amount of variation or dispersion in a set of values.

Front

How does increasing the sample size affect the standard deviation?

Back

Increasing the sample size generally leads to a more accurate estimate of the population standard deviation, but it does not directly affect the standard deviation of the sample itself.