quartile

(noun)

any of the three points that divide an ordered distribution into four parts, each containing a quarter of the population

Related Terms

Examples of quartile in the following topics:

  • Box Plots

    • To find the quartiles, first find the median or second quartile.
    • The median or second quartile is 7.
    • The first quartile marks one end of the box and the third quartile marks the other end of the box.
    • The first quartile is 2, the median is 7, and the third quartile is 9.
    • What is the median, the first quartile, and the third quartile for each data set?

  • Interquartile Range

    • The values that divide these parts are known as the first quartile, second quartile and third quartile (Q1, Q2, Q3).
    • This median separates the third and fourth quartiles.
    • Subtract the lower quartile from the upper quartile: 21-2=19.
    • A box plot separates the quartiles of the data.
    • The box starts at the lower quartile and ends at the upper quartile, so the difference, or length of the boxplot, is the IQR.

  • Measures of the Location of the Data

    • The common measures of location are quartiles and percentiles (%iles).Quartiles are special percentiles.
    • The first quartile, Q1 is the same as the 25th percentile (25th %ile) and the third quartile, Q3 , is the same as the 75th percentile (75th %ile).
    • It is the difference between the third quartile (Q3) and the first quartile (Q1):
    • Find the third quartile: The third quartile is the same as the 75th percentile.You can "eyeball" this answer.
    • The third quartile, Q 3 , is the 38th value which is an 8.

  • Lab: Continuous Distribution

    • In theory, based upon the distribution X∼U(0,1), complete the following. 3.1. µ =3.2 σ = 3.3 1st quartile = 3.4 3rd quartile = 3.5 median = __________
    • For each part below, use a complete sentence to comment on how the value obtained from the data compares to the theoretical value you expected from the distribution in the section titled "Theoretical Distribution. " 1.1 minimum value:1.2 1st quartile: 1.3 median: 1.4 third quartile: 1.5 maximum value: 1.6 width of IQR: 1.7 overall shape:

  • Student Learning Outcomes

    • Recognize, describe, and calculate the measures of location of data: quartiles and percentiles.

  • Practice 2: Spread of the Data

    • Calculate the mean, median, standard deviation, first quartile, the third quartile and the IQR.

  • Measures of Relative Standing

    • The common measures of relative standing or location are quartiles and percentiles.
    • The 25th percentile is also known as the first quartile (Q1), the 50th percentile as the median or second quartile (Q2), and the 75th percentile as the third quartile (Q3).
    • To calculate quartiles and percentiles, the data must be ordered from smallest to largest.
    • Recall that quartiles divide ordered data into quarters.
    • Outline how percentiles and quartiles measure relative standing within a data set.

  • Practice 1: Center of the Data

  • Practice 1: Uniform Distribution

    • Exercise 5.6.12: Find the third quartile of ages of cars in the lot.
    • The third quartile is:

  • Lab: Descriptive Statistics