Question

Chi-squared test of independence and goodness-of-fit

Q1) When new novels are promoted at bookshops, a display is sometimes arranged with copies of the same book with differently coloured covers. A publishing company wanted to find out whether the colour of the cover has an effect on sales. For a new novel, the publisher sent copies to a number of large bookshops. Total sales after a week for each coloured cover were as follows:

Colour	Red	Blue	Green	Yellow	White
Sales	107	122	133	90	141

a) Using these data and a chi-squared test, decide whether cover colour is related to sales.

b) Complaints were received from members of the public that the yellow cover was tasteless and vulgar, as a result of which that cover was removed from sale. Repeat the analysis in a) for the remaining red, blue, green and white covers. Interpret your results.

Answer 1