Comparing Measures of Variation

Front

What is the interquartile range (IQR)?

Back

The interquartile range (IQR) is a measure of statistical dispersion, representing the range of the middle 50% of a dataset. It is calculated as the difference between the third quartile (Q3) and the first quartile (Q1).

Front

How do you calculate the IQR?

Back

To calculate the IQR, first find Q1 (the median of the lower half of the data) and Q3 (the median of the upper half of the data). Then, subtract Q1 from Q3: IQR = Q3 - Q1.

Front

What does a box-and-whisker plot represent?

Back

A box-and-whisker plot visually represents the distribution of a dataset, showing the median, quartiles, and potential outliers.

Front

What is the median in a dataset?

Back

The median is the middle value of a dataset when it is ordered from least to greatest. If there is an even number of observations, the median is the average of the two middle numbers.

Front

What percent of data is below the first quartile (Q1)?

Back

25% of the data is below the first quartile (Q1).

Front

What percent of data is between the first quartile (Q1) and the third quartile (Q3)?

Back

50% of the data is between the first quartile (Q1) and the third quartile (Q3).

Front

What is the purpose of using box-and-whisker plots?

Back

Box-and-whisker plots are used to summarize and compare distributions of data, highlighting the median, quartiles, and potential outliers.

Front

If the IQR is small, what does that indicate about the data?

Back

A small IQR indicates that the data points are closely clustered around the median, suggesting low variability.

Front

If the IQR is large, what does that indicate about the data?

Back

A large IQR indicates that the data points are spread out over a wider range, suggesting high variability.

Front

What is a quartile?

Back

A quartile is a type of quantile that divides a dataset into four equal parts, with each part representing 25% of the data.