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9 
Adding a lineofbestfit in Excel Use the equation of the lineofbestfit to predict 'y' values from a 'x' value Use the equation of the lineofbestfit to predict 'x' values from a 'y' value 
Class notes, Blank notes 
A line can be drawn to ‘fit’ the relationship Using Excel – right click on a data point and 'Add Trend line' and tick the ‘show equation’ box near the bottom The equation line can then be used to predict ‘y’ and ‘x’ values
Eg y = 1.026x  0.3249 so B = 1.026×10  0.3249 = 9.9351 which should be rounded sensibly B = 9.9 and remember units
Predicting ‘x’ from a given ‘y’ is involves solving an equation.Eg If Variable ‘B’ = 14, predict a value for ‘A’ y = 1.026x  0.3249 so 14 = 1.026×A  0.3249 14.3249 = 1.026×A 13.96189 = A Round sensibly A = 14 Check the if the solution matches the graph
Examples1) If a student had a Maths score of 14, predict their English Score.
2) If a student had a Maths score of 6, predict their English Score.
3) If a student had a English score of 8, predict their Maths Score.
4) If a student had a English score of 16, predict their Maths Score.
5) How accurate are these predictions?
