Excel's intercept function takes the data points that define a line on a graph and calculates the y value for the point on the graph where x is equal to zero.

With line graphs, you have a choice between connecting the plots point-to-point, or using a line of best fit. Joining dots point to point is essential to show fluctuations in data - for instance ...

An average speed for a journey can be found from a distance-time graph by working out the gradient of the line between the two points of interest. This is like using a car's milometer and clock to ...