Stats 2.1 Percentile, Zscore, Transform Data

Front

What is a percentile?

Back

A percentile is a measure used in statistics indicating the value below which a given percentage of observations in a group of observations falls.

Front

How is the IQR (Interquartile Range) calculated?

Back

IQR is calculated as the difference between the third quartile (Q3) and the first quartile (Q1): IQR = Q3 - Q1.

Front

What effect does adding a constant to all values in a data set have on the mean?

Back

Adding a constant to all values increases the mean by that constant.

Front

What effect does adding a constant to all values in a data set have on the IQR?

Back

Adding a constant to all values does not change the IQR.

Front

How do you find the 25th percentile (Q1) in a data set?

Back

To find Q1, arrange the data in ascending order and find the median of the lower half of the data.

Front

What is a Z-score?

Back

A Z-score indicates how many standard deviations an element is from the mean of the data set.

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

What is the purpose of transforming data?

Back

Transforming data can help normalize the distribution, making it easier to analyze and interpret.

Front

What happens to the median when a constant is added to all values in a data set?

Back

The median increases by that constant.

Front

How do you determine the percentile rank of a value in a data set?

Back

Percentile rank = (number of values below X / total number of values) * 100.