Quartiles Flashcards

Values that divide a data set into four equal parts, each containing 25% of the data.

The value that separates the lowest 25% of the data from the rest. It is the median of the lower half of the data.

The middle value of a data set when it is ordered. It separates the data into two equal halves.

The value that separates the highest 25% of the data from the rest. It is the median of the upper half of the data.

The difference between the upper quartile (Q3) and the lower quartile (Q1). It measures the spread of the middle 50% of the data.

Order the data, find the median of the lower half of the data (not including the overall median if the number of data points is odd).

Order the data, find the median of the upper half of the data (not including the overall median if the number of data points is odd).

The interquartile range shows how spread out the middle 50% of the data is. A smaller IQR indicates less variability.

The lower quartile (Q1), median (Q2), and upper quartile (Q3) can be estimated by finding the 25th, 50th, and 75th percentiles on the graph.

The IQR is less affected by extreme values (outliers) than the range, making it a better measure of spread for skewed data.