A soft drink factory fills cans of soda water by setting a timer on a filling machine. It has been found that the distribution of the amount of soda water the machine puts into a can is normal with standard deviation of 1 ml.
(a) If the company wants 99.9% of all its cans of soda water to have at least 375 ml as printed on the container, what mean amount should the filling machine be set to put in each can?
(b) Using the mean obtained in part (a), find out
(i) the range of the middle 70% of cans.
(ii) the minimum volume of the top 2% of cans.