Practice question · Numerical answer
A regression line has equation y = 2x + 1. For the observed data point (3, 10), compute the residual.
Hints
- The residual is the observed value minus the value the line predicts.
- The line predicts 2(3) + 1 = 7.
Show the answer
3 (answers within ±0.01 count)
Why
The prediction is 7 and the observation is 10, so the residual is 10 - 7 = 3: the point sits 3 above the line. Least squares chooses the line that makes the sum of these residuals, squared, as small as possible.
Practise Correlation and Regression
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