Comparing Data Sets

 

What Does It Mean to Compare Data?

When comparing two sets of data, we look at:

• Measures of average (mean, median, or mode)
• Measures of spread (range or interquartile range)

We use this to say:

• Which group performed better
• Which group had more consistent results

 

How to Compare Data Sets

When given two data sets, compare:

1. Averages

Choose the appropriate average:

• Use median if there are outliers
• Use mean if the data is fairly consistent
• Use mode for categorical or most frequent values

2. Spread

• Use range or interquartile range (IQR)
• A smaller range or IQR means the data is more consistent (less spread out)

 

Example

Two classes take the same maths test. Their scores are summarised below:

 

Class	Median	Range
A	68	12
B	61	18

 

Compare the results:

• Median comparison:
  • Class A has a higher median score (68 vs 61).
  • This suggests that Class A performed better on average.
• Range comparison:
  • Class A has a smaller range (12 vs 18).
  • This suggests that Class A’s scores were more consistent (less spread out).

 

 

 

Exam Ready Phrases

"The [mean/median] of Group A is higher than Group B. This suggests Group A performed better."

"The range of Group A is lower than Group B. This suggests Group A's results were more consistent."

"Group B has a larger spread, meaning more variation in their scores."