Linear regression and correlation flashcards

Question 1

What does the correlation coefficient $r$ measure?

Accepted Answer

$r$ measures the direction and strength of the linear relationship between two quantitative variables; $-1\le r\le 1$.

Question 2

What is the least squares regression line?

Accepted Answer

The line $\hat y=b_0+b_1x$ that minimizes the sum of squared residuals $\sum (y_i-\hat y_i)^2$.

Question 3

When is prediction (interpolation) more reliable than extrapolation?

Accepted Answer

Predictions are more reliable when $x$ is within the observed range (interpolation). Extrapolation uses $x$ values outside the data range and is riskier because the linear trend may not continue.

Linear regression and correlation flashcards

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