Interquartile Range Worksheet
A Grade 9 math worksheet focusing on understanding and calculating the interquartile range from data sets and box plots.
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Interquartile Range Worksheet
Name:
Date:
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Read each question carefully and provide your answer in the space provided. Show all your work for calculation questions.
1. Define the following terms:
a) Lower Quartile (Q1):
b) Upper Quartile (Q3):
c) Interquartile Range (IQR):
2. Calculate the Interquartile Range (IQR) for the following data set:
Data Set: 12, 15, 18, 20, 22, 25, 28, 30, 32
First Quartile (Q1):
Third Quartile (Q3):
Interquartile Range (IQR):
3. The box plot below represents the scores of students on a math test.
a) What is the median score?
b) What is the Interquartile Range (IQR) for this data set?
4. Which of the following statements about the Interquartile Range (IQR) is true?
The IQR is always smaller than the range.
The IQR is not affected by outliers.
The IQR is the difference between the highest and lowest values.
The IQR represents the middle 25% of the data.
5. A company recorded the number of sales made by its employees in a month:
Sales: 10, 12, 15, 18, 20, 22, 25, 30, 35, 40, 50, 80
Calculate the IQR for this data set. Explain what the IQR tells you about the sales data.