Quartiles and Their Calculations

Front

What is a quartile?

Back

A quartile is a type of quantile that divides a data set into four equal parts, each containing 25% of the data.

Front

How do you calculate the first quartile (Q1)?

Back

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

Front

How do you calculate the second quartile (Q2)?

Back

Q2 is the median of the data set, which divides the data into two equal halves.

Front

How do you calculate the third quartile (Q3)?

Back

To find Q3, arrange the data in ascending order and find the median of the upper half of the data set.

Front

Given x=(3, 3, 5, 5, 5, 9, 9), what is Q1?

Back

Q1 = 4

Front

Given x=(2, 4, 5, 6, 7, 9), what is Q2?

Back

Q2 = 5.5

Front

Given x=(2, 4, 5, 6, 7, 9), what is Q3?

Back

Q3 = 7

Front

What is the formula for finding the position of Q1 in a data set?

Back

Position of Q1 = (n + 1) / 4, where n is the number of data points.

Front

What is the formula for finding the position of Q2 in a data set?

Back

Position of Q2 = (n + 1) / 2, where n is the number of data points.

Front

What is the formula for finding the position of Q3 in a data set?

Back

Position of Q3 = 3(n + 1) / 4, where n is the number of data points.