Line of best fit

• A line of best fit it a type of trend line; it shows the 'trend' of the data.

• We can use trend lines to estimate values at points where we have no data.

• A line of best fit is always a straight line, so must be drawn with a ruler.

• There should be as many point above the line as below the line.

• The line should be the minimum total distance away from all the points.

Positive Correlation

• If the line of best fit starts near the origin and goes diagonally upward, we say that the two measurements of data have a positive correlation.

• A positive correlation means that if one measurement increases, the other measurement will increase too.

• The closer the data ponits are to the line, the stronger the correlation.

Negative Correlation

• If the line of best fit starts near the tip of one axis then goes diagonally downwards to the tip of the other axis, we say that the two measurements of data have a negative correlation

• A negative correlation means that if one measurement increases, the other measurement will decrease.

• The closer the data ponits are to the line, the stronger the correlation.