3. If the equation of a least squares regression line is y = -5.6 -0.78x, and R 2 = 48%, what is the value of the correlation coefficient, r? 4. The equation of the least squares regression line relating age and score on the eye sight test was found to be: score on the eye sight test = 220.0 - 1.5 age Use this equation to predict the eye sight test score for a person aged a) 67 years b) 97 years 5. The number of visitors recorded at a garden centre in each quarter of one year are as follows: Quarter Summer Autumn Winter Spring Visitors 2305 1563 988 3212 Calculate the seasonal index for Winter.