Simple Linear Regression Analysis
Statistics • Simple Linear Regression
Frequently Asked Questions
What does simple linear regression analysis tell you?
It describes and models the linear relationship between one explanatory variable x and one response variable y. The fitted line provides an estimated slope and intercept that summarize how y changes as x changes.
What does the slope b1 mean in a regression line?
The slope b1 is the estimated change in the predicted response y for a one-unit increase in x. Its sign indicates whether the relationship is positive or negative.
What is R^2 in simple linear regression?
R^2 is the proportion of the total variation in y explained by the fitted linear model. Values closer to 1 indicate a stronger linear fit, while values closer to 0 indicate a weaker linear fit.
How do you test whether there is a significant linear relationship?
A common test is H0: beta1 = 0 versus an alternative that beta1 is not 0 (or is greater or less than 0). The calculator reports a test statistic and p-value to decide whether the slope differs from 0 at the chosen alpha.
What is the difference between a confidence interval and a prediction interval in regression?
A confidence interval estimates the mean response at a given x0, while a prediction interval estimates a single future observation at x0. Prediction intervals are wider because they include additional individual-to-individual variability.