Least Squares Regression Calculator

Find the line of best fit using least squares method with correlation analysis

Enter Data Points

X Value
Y Value
Action

Valid data points: 2 / 2

Least Squares Method

1

Calculate distances

Find vertical distances from points to line

2

Square the distances

Square each distance to eliminate negatives

3

Minimize sum

Find line that minimizes sum of squared errors

Key Formulas

Slope (a):
a = (n·Sxy - Sx·Sy) / Δ
Intercept (b):
b = (Sxx·Sy - Sx·Sxy) / Δ
Correlation (r):
r = (n·Sxy - Sx·Sy) / √[(n·Sxx - Sx²)(n·Syy - Sy²)]

Tips

R² close to 1 indicates strong linear relationship

Watch out for outliers that can skew results

More data points generally improve accuracy

Consider non-linear models for curved relationships

Understanding Least Squares Regression

What is Least Squares Regression?

Least squares regression is a statistical method used to find the line of best fit through a set of data points. It minimizes the sum of squared vertical distances between the observed data points and the fitted line.

Why Use This Method?

  • Provides the best linear unbiased estimate
  • Widely accepted and mathematically robust
  • Easy to interpret and implement
  • Foundation for more complex statistical models

Applications

Economics & Finance

Predicting stock prices, analyzing market trends

Science & Engineering

Calibrating instruments, modeling physical phenomena

Machine Learning

Linear regression models, feature selection

Quality Control

Process optimization, trend analysis

Understanding the Results

Correlation Coefficient (r)

  • r = 1: Perfect positive correlation
  • r = 0: No linear correlation
  • r = -1: Perfect negative correlation
  • |r| > 0.8: Strong correlation
  • |r| < 0.3: Weak correlation

R-Squared (R²)

  • R² = 1: Perfect fit (100% variance explained)
  • R² = 0: No explanatory power
  • R² > 0.7: Good fit
  • R² < 0.3: Poor fit
  • Represents proportion of variance explained