Home / Statistical Tools / Analysis Tools / Correlation and Covariance / How-To / Spearman Correlation
Spearman Correlation¶
Spearman Correlation computes the correlation between variables from the ranks of their values rather than from the raw values.
Goal¶
Measure rank-based correlations between hours studied, test scores, and class rank for a group of students.
Sample Data¶
Press Copy for Excel, then paste the table into a blank worksheet.
| Hours Studied | Test Score | Class Rank |
|---|---|---|
| 2 | 62 | 25 |
| 4 | 68 | 19 |
| 6 | 72 | 14 |
| 8 | 81 | 11 |
| 10 | 85 | 7 |
| 3 | 71 | 16 |
| 5 | 70 | 18 |
| 7 | 79 | 8 |
| 9 | 83 | 9 |
| 11 | 89 | 4 |
Each row represents one student. Hours Studied and Test Score rise together. Class Rank runs the other way, so its correlations with the other two columns come out negative.
Steps¶
-
Put the data in Excel
Press Copy for Excel above the table, click cell A1 in a blank worksheet, and press Ctrl+V. The header row lands in row 1 and the 10 data rows in rows 2 through 11.
-
Launch the analysis
From the Excel ribbon, select QXL Stat Tools → Analysis Tools → Correlation and Covariance → Spearman's Correlation (Non-normal).
-
Select your data
In the Data Selection window, select cells A1:C11 (the header row plus all 10 data rows across all three columns). Make sure Data in Columns and First Row/Column is Header are selected, then click Next >.
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Configure the analysis
In the Correlation dialog:
- Data Columns: "Hours Studied", "Test Score", and "Class Rank" should all be checked
Click Finish to generate the correlation matrix.
Result¶
Quantum XL creates a 3×3 Spearman correlation matrix with p-values for each pair:
- Hours Studied vs. Test Score: coefficient 0.963636.
- Hours Studied vs. Class Rank: coefficient -0.927273.
- Test Score vs. Class Rank: coefficient -0.963636.
All three p-values are very small. p-values at or below 0.05 are shown in bold red.
Spearman and Pearson
Spearman ranks each value before computing the correlation. Pearson computes it from the raw values.