QUESTION ONE (16 MARKS) a) Suppose the Cleaning Services reported that the mean payment received for the 1 week was RM2,800. Assume the standard deviation is RM450 and that the payment received follow a normal distribution. What percentage of the payment are more than RM3, 100 but less than RM3,500? (4 marks) b) The manufaturer of a plastic bag reports that the mean number of plastic bag machine will print before it needs replacing is 12,200 plastic bag. The distribution of plastic bag produced for one machine closely follows the normal probaility distribution and the standard deviation of 820 pages. The manufacturer wants to provide guideline to potential customers as to how long they can expect a machine to last. How many plastic bag should the manufacturer produce for each machine if it wants to be correct 99% of the time