SaiBook.us Statistics

Lesson

Title: Measures of variation-Interquartile range

Grade: 9-a Lesson: S1-L8

Explanation: Hello students, let us learn a new topic in statistics today with definitions, concepts, examples, and worksheets included.

Lesson:

Definition: Measures of variation

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Explanation: The three most commonly used measures of variation are

Definition: Interquartile Range

The interquartile range (IQR) is the range of the middle 50 percent of the data, the difference between the third quartile (\$Q_3\$) and the first quartile (\$Q_1\$).

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Explanation: \$IQR\$ = \$Q_3 -Q_1\$

where,IQR = Interquartile Range,

\$Q_3\$ = \$3_(rd)\$ quartile

\$Q_1\$ = \$1_(st)\$ quartile

Definition: Methods of interquartile Range

Inclusive method:This method includes the median in identifying the quartiles and used in even and odd number of data sets.
Exclusive method:This method excludes the median when identifying Q1 and Q3. Mostly,this method is used in odd number of data sets.

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Explanation: Steps for inclusive method:

Arrange the data in ascending order
Find out the median
Find \$Q_1\$ i.e,median(or)middle of the first half,\$Q_3\$ i.e,median(or)middle in the second half.
Calculate the IQR.