What is the least squares regression line and what does it show you?
The least squares regression line is the posh name for the ‘line of best fit’ that we can apply to a scatter graph. It shows the trend in a set of data with 2 variables. It is normally written in the form y = a + bx, where b = gradient of line and a = y-intercept (like the y=mx + c which you probably learnt in GCSE) Equations for finding a & b are given in the standard A-Level formulae books (S1).
