Measurement & data · TEKS 7.12A, 7.12C
Comparing two data sets
To compare two groups, look at their CENTER (mean or median) and their SPREAD (range or IQR).
Key steps
- Mean = sum ÷ count. Median = middle value when sorted.
- Range = max − min. IQR = Q3 − Q1 (the middle 50%).
- Box plot: min, Q1, median, Q3, max.
- A bigger range or IQR means the data is more spread out.
Worked example
A: min 10, Q1 15, med 22, Q3 30, max 40. B: min 12, Q1 20, med 24, Q3 28, max 35. Which is more spread out?
- IQR A = 30 − 15 = 15. IQR B = 28 − 20 = 8.
- Answer: Team A’s middle half is more spread out.
Watch out: Sort the list before finding the median.
Practice
5 questions with new numbers every set. Get 4 of 5 to mark this topic as practiced.