University of Chicago Booth School of Business John Birge ASSIGNMENT Concept Check #1 1. (Capacity analysis.) Each circle below represents a single server, and the time indicated represents the service time for a single job. Compute the capacity (in jobs per minute) and cycle time (in minutes) for each of the following process flows. Assume no queues form in front of servers, the service time for each job is exactly as indicates (i.e. deterministic), and throughput equals capacity. a. [1 point] 3 min b. [1] 3 min 2 min 2 min 2 min c. [1] d. [1] 3 min OR 2 min e. [1] 3 min AND 2 min 2. [5] (Little’s Law.) Read the article “McD’s Service Stalls at Drive-Thru” (on Canvas), which appeared on the front page of Crain’s Chicago Business on January 2, 2006. According to QSR magazine, the original data source, the “average time in seconds” reported in the figure “was determined based on how long it took from when the vehicle stopped at the speaker to when the entire order was received.” So, it does not include the waiting time before arriving at the speaker. The figure entitled “Time is Money”, which does the financial analysis, has serious flaws in the operational part of the analysis. What’s wrong? Use your own personal experience of how the drive-thru at McDonald’s operates. 3. [4] (Basic concepts in probability.) The demand for JJ Jackson’s Navy coat is a normally distributed random variable with mean 800 and standard deviation 236.64. Hint: You may want to take a look at the “Basic Concepts in Probability” document. (See Session 1 readings on Canvas) a. [2] What is the probability that the demand is less than 800? b. [2] The probability than demand is less than x is 0.814. What is x?
