Nine students follow a diet over the Easter holidays: their weights (in kg) before and after the diet are:
before 66.4 47.3 57.4 50.2 55.5 56.1 54.5 47.6 59.9
after 62.7 47.1 56.1 49.0 52.8 49.7 53.6 46.0 59.0
Stating the assumptions on which your arguments and conclusions are based, summarise the statistical evidence regarding the effectiveness of this diet.