Find the range in the following data 9, 15, 6, 20, 24, 18, 12, 8, 20, 10, 5.

Analyze the question: The range measures how spread out the data is. It is the difference between the largest and smallest values.

Concept: Range = Highest value − Lowest value

Solution:

Data: 9, 15, 6, 20, 24, 18, 12, 8, 20, 10, 5

Arranged in order: 5, 6, 8, 9, 10, 12, 15, 18, 20, 20, 24

• Highest value = 24
• Lowest value = 5

Range = 24 − 5 = 19

Answer: The range is 19, which is option C.

Tip: Students often pick the highest value (24) by mistake, which is option A here. Remember that the range is a difference, so always subtract the smallest value from the largest. Also, repeated values such as 20 do not affect the range, so you only need to find the two extremes.