The variables x x\,x and y y\,y are recorded and the results are shown in the table below
| xxx | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| yyy | 429 | 754 | 871 | 1119 | 2478 | 2653 | 3050 | 3279 | 5470 | 7439 |
The data is coded using the changes of variable r=xr = xr=x and s=log10ys = \log_{10} ys=log10y
The product moment correlation coefficient for the coded data is 0.98 Comment on r r\,r for this model and therefore justify the use of a model in the form y=abxy = ab^xy=abx where a a\,a and b b\,b are constants
The regression line of r r\,r on s s\,s is found to be s=2.60+0.127rs = 2.60 + 0.127rs=2.60+0.127r
Find the values of a a\,a and bbb, give your answers to 3 significant figures
104 exam-style questions on OCR A Level Maths 1.6 Exponentials and Logarithms, covering 1.6.1 Properties of the exponential function, 1.6.2 Gradient of e^(kx) (A-level only), 1.6.3 Definition of the logarithm, 1.6.4 The natural logarithm function, 1.6.5 ln x as inverse of e^x, 1.6.6 Laws of logarithms, 1.6.7 Equations involving exponentials, 1.6.8 Reduction to linear form, and 1.6.9 Modelling using exponential functions. Each one has a worked solution and a mark scheme showing where the marks go.