Calculating Spearman's rank correlation coefficient (AQA GCSE Statistics): Flashcards
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What does Spearman's rank correlation coefficient measure?
What does Spearman's rank correlation coefficient measure?
It measures the strength of relationship between ranks.
What is the range of Spearman's rank correlation coefficient?
What is the range of Spearman's rank correlation coefficient?
The range is from -1 to +1.
How do you rank tied values in Spearman's correlation?
How do you rank tied values in Spearman's correlation?
Assign them the average of their ranks.
What is the formula for Spearman's rank correlation?
What is the formula for Spearman's rank correlation?
r_s = 1 - (6Σd²)/(n(n²-1))
Calculate d² for ranks 2 and 4 with d = -2.
Calculate d² for ranks 2 and 4 with d = -2.
d² = 4.
If rs = 0.81, what type of correlation is indicated?
If rs = 0.81, what type of correlation is indicated?
A strong positive correlation.
What does rs = -1 indicate?
What does rs = -1 indicate?
Perfect negative correlation.
Why is Spearman's correlation useful for non-linear data?
Why is Spearman's correlation useful for non-linear data?
It focuses on ranks, not actual values.
What should you do before applying the Spearman formula?
What should you do before applying the Spearman formula?
Rank your data first.
What does rs close to 0 indicate?
What does rs close to 0 indicate?
A weak correlation.