Brainlag PlusCorrelation, lines of best fit, outliers, interpolation and extrapolation, populations, samples and bias.
Correlation and the line of best fit
A scatter graph plots pairs of values.
If the points go up from left to right there is positive correlation; down, negative correlation; no pattern, no correlation. Describe it in context: "the longer students revised, the higher their marks tended to be."
A line of best fit is a straight line through the middle of the points, with about as many above it as below. Read an estimate from the line, not from the nearest point. A point far from the pattern is an outlier: ignore it when you draw the line.
The rest of this lesson and its 8 practice questions are in Plus.
Screen 1 of 4, free to read.
- 8 exam-style questions, marked as you go, each with a worked solution
- Anything you get wrong is saved to your flashcards