Practice Exercises: Finding Quartiles and IQR in Algebra 1 Data Sets

📚 Topic Summary

Finding quartiles and the Interquartile Range (IQR) helps us understand the spread of data in a set. Quartiles divide the data into four equal parts. The first quartile (Q1) is the median of the lower half of the data, the second quartile (Q2) is the median of the entire dataset, and the third quartile (Q3) is the median of the upper half. The IQR is the range between Q3 and Q1, showing the spread of the middle 50% of the data. Let's practice!

🧠 Part A: Vocabulary

Match the term with its definition:

1. Term: Median
2. Term: Quartile
3. Term: Interquartile Range (IQR)
4. Term: Lower Quartile (Q1)
5. Term: Upper Quartile (Q3)

Definitions:

1. The value separating the lower 25% of the data from the upper 75%.
2. The middle value in a sorted dataset.
3. A value that divides the data into four equal parts.
4. The value separating the upper 25% of the data from the lower 75%.
5. The difference between the upper and lower quartiles.

📝 Part B: Fill in the Blanks

The __________ (1) is the middle value of a dataset when it's arranged in order. __________ (2) divide the data into four equal parts. The __________ (3) is the difference between Q3 and Q1, representing the spread of the middle 50% of the data. The lower quartile is also known as __________ (4), and the upper quartile is known as __________ (5).

🤔 Part C: Critical Thinking

Why is the IQR a more resistant measure of spread than the range (maximum value - minimum value)? Explain your answer.