A sample of eight employees is taken from the production department of a light engineering factory. The data below relate to the number of weeks' experience in the wiring of components, and the number of components which were rejected as unsatisfactory last week.

Employee A 8 C D E F G H Weeks' experience (X) 4 5 7 9 10 11 12 14 No. of rejects ( Y) 21 22 15 18 14 14 11 13 I:x = 72 I:y = 128 I:xy = 1069 I:x2 = 732 I:y2 = 2156 REQUIRED

(a) Draw a scatter diagram of the data.

(b) Calculate a coefficient of correlation for these data and interpret its value.

(c) Find the least squares regression equation of rejects on experience 149 Predict the number of rejects you would expect from an employee with 1 week of experience ICMA, FS, •, Section B, Mathematics and Statistics, May 1982.
a Foundation Stage