Percentiles and Normal Distribution Review

Front

What does a z-score of 2.15 mean?

Back

The score is 2.15 standard deviations above the mean.

Front

What does σ represent in statistics?

Back

Population/distribution standard deviation.

Front

What are the characteristics of a normal distribution?

Back

Roughly unimodal and symmetric.

Front

What is the Empirical Rule for normal distributions?

Back

68% of data is within 1 standard deviation, 95% within 2, and 99.7% within 3 standard deviations of the mean.

Front

Which of the following is NOT part of the Empirical Rule? 100% of data is within what?

Back

4 standard deviations of the mean.

Front

If x=12 has a z-score of 2.2 and the standard deviation is 3, what is the value of μ?

Back

5.4

Front

What is a z-score?

Back

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

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 it mean if a data set is skewed?

Back

It means the data is not symmetrically distributed; it has a tail on one side.

Front

What is the significance of the mean in a normal distribution?

Back

The mean is the central point around which the data is distributed.