Calculator Input
Example Data Table
| X | Y | XY | X² | Y² |
|---|---|---|---|---|
| 2 | 5 | 10 | 4 | 25 |
| 4 | 7 | 28 | 16 | 49 |
| 6 | 9 | 54 | 36 | 81 |
| 8 | 11 | 88 | 64 | 121 |
Formula Used
Sum of XY: Σxy = x₁y₁ + x₂y₂ + x₃y₃ + ... + xₙyₙ
Mean X: x̄ = Σx / n
Mean Y: ȳ = Σy / n
Cross Deviation: SP = Σxy - (Σx × Σy / n)
Sample Covariance: sxy = SP / (n - 1)
Population Covariance: σxy = SP / n
Correlation: r = SP / √(Sxx × Syy)
Regression Slope: b = SP / Sxx
How to Use This Calculator
- Enter paired x and y values in the text area.
- Put each pair on a new line.
- Use optional scale and shift fields when values need adjustment.
- Select decimal places for rounded output.
- Press Calculate to view sum of xy and related results.
- Use CSV or PDF buttons to save the report.
Statistics Sum of XY Calculator Guide
Purpose
The statistics sum of xy calculator helps you study paired numerical data. It multiplies every x value by its matching y value. Then it adds all products into one useful total. This total is written as Σxy. It is important in regression, correlation, covariance, and many data tables.
Why Σxy Matters
Paired values often describe connected measurements. A teacher may compare study hours and scores. A business may compare price and demand. A researcher may compare weight and height. The x column gives one variable. The y column gives another variable. Their product shows how both variables move together. The total of those products supports deeper analysis.
Advanced Output
This calculator does more than basic multiplication. It also finds Σx, Σy, Σx², and Σy². These totals help build regression equations. They also support covariance and correlation calculations. The tool computes cross deviation. It gives sample covariance and population covariance. It also estimates the correlation coefficient. A simple regression slope and intercept are included.
Data Adjustment
Sometimes raw values need conversion before analysis. You may multiply x or y values by a scale. You may also add a shift. This is useful for unit conversion. It also helps when coded data must be restored. The calculator keeps raw and adjusted values visible. That makes checking easier.
Practical Use
Enter one x,y pair on each line. The calculator accepts commas, spaces, semicolons, and pipes. This flexible entry method helps with copied data. After calculation, review the table. Check each xy product. Then review the final totals. Export the result when you need a saved record.
Accuracy Notes
Clean data gives better results. Make sure each x value has one matching y value. Remove blank or incomplete rows. Use the rounding field only for display. The internal calculations still use numeric values. For serious statistical work, check outliers first. A single extreme pair can change Σxy, covariance, and correlation.
FAQs
What is the sum of xy?
It is the total of all products made by multiplying each x value with its matching y value.
Why is Σxy used in statistics?
It helps calculate covariance, correlation, regression slope, and other measures for paired data analysis.
Can I enter negative numbers?
Yes. Negative values are supported. They affect xy products and final statistical measures normally.
Can I paste data from a spreadsheet?
Yes. Paste paired values line by line. Use commas, spaces, semicolons, or pipes between x and y.
What does cross deviation mean?
Cross deviation shows the adjusted shared movement between x and y after accounting for their totals.
What is the difference between sample and population covariance?
Sample covariance divides by n minus one. Population covariance divides by n. Use sample covariance for sampled data.
Does this calculator find correlation?
Yes. It estimates the correlation coefficient when variation exists in both x and y values.
What are scale and shift fields for?
They adjust values before calculation. Use them for conversions, coded variables, or transformed statistical data.