For all 348 Local Authorities, the official OCR workbook gives the regression line y=1.283x−1.452y=1.283x-1.452y=1.283x−1.452, where x x\,x and y y\,y are the 2001 and 2011 percentages working mainly at or from home.
Estimate the 2011 percentage for a Local Authority with 2001 percentage 18%.
Calculate the residual if its actual 2011 percentage is 24.8%.
Interpret the sign of the residual.
Give one reason not to use the line for x=40x=40x=40.
121 exam-style questions on OCR A Level Maths 2.2 Data Presentation and Interpretation, covering 2.2.1 Tables and diagrams for single variable data, 2.2.2 Area in a histogram, 2.2.3 Scatter diagrams and regression lines, 2.2.4 Informal interpretation of correlation, 2.2.5 Correlation and causation, 2.2.6 Measures of average and spread, 2.2.7 Calculations of mean and standard deviation, 2.2.8 Outliers, 2.2.9 Selecting or critiquing data presentation, and 2.2.10 Cleaning data. Each one has a worked solution and a mark scheme showing where the marks go.