A scatter graph plots pairs of data, such as hours of revision and test score. If the points go up from left to right, there is positive correlation. If they go down, there is negative correlation. If there is no pattern, there is no correlation.
A line of best fit is a straight line through the middle of the points. You can use it to estimate a value, but only inside the range of the data. Correlation does not prove that one thing causes the other.
Worked example
As temperature goes up, more ice creams are sold. What type of correlation is this?
- Both quantities increase together.
- That pattern goes up from left to right.
Answer:positive correlation
Key words
- correlation
- a relationship between two variables
- line of best fit
- a straight line that follows the trend
- outlier
- a point far from the others
Practise this
New questions every time.
Common Core-referenced: 8.SP.A.1, 8.SP.A.2