(Ref. Ch. 16 Oakshott, p.433) Example 20.1: The amount of cotton used daily by the Just Shirts Company is normally distributed with an average of 1000 metres and a standard deviation of 250 metres. The lead time required to receive an order of cotton from the supplier is constant at 7 days. ( What is the mean and the standard deviation of the total amount of cotton used in 7 days? Select one: O a. mean = 1000, s.d. = 661.44 0 b. mean = 7000, s.d. = 661.44 O c. mean = 7000, s.d. = 41.83 d. mean = 1000, s.d. = 41.83 O e. mean = 1000, s.d. = 250 Refer to Example 20.1 above. (ii) If the Just Shirts wants to limit the probability of a running out of cotton during the lead time to 5%, what is the value of z = 24 that we use to find the re-order level? Select one: O a. 1.645 O b. 1.96 c. 2.33 d. 2.575 e. 3.14 Choose the most proper one that completes the following sentence: In order to determine the re-order level, if we choose to use a smaller probability of running out of stock, then: Select one: O a. we will have a higher level of the buffer stock b. we will have a lower level of the buffer stock. C. We will still keep the same level of the buffer stock. 0