10.112 Safety Programs The data shown here were collected on lost-time accidents (the figures given are mean work-hours lost per month over a period of one year) before and after an industrial safety program was put into effect. Data were recorded for six indus- trial plants. Do the data provide sufficient evidence to indicate whether the safety program was effective in reducing lost-time accidents? Test using a = 0.01.

Plant Number 1 2 3 4 5 6 Before program After program 38 64 42 70 58 30 31 58 43 65 52 29