Why should dollar and relative differences be used jointly in variance analysis?

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Below you’ll find an operations summary of a manufacturing company.   # of Machine Annual Fixed Cost Output 1 9,600 0-300 2 15,000 300-600 3 20,000 600-900 Variable Cost 10/unit Revenue 40/unit What is the BEP for the first interval?

Joe Ferris is a stock trader on the floor of the New York Stock Exchange for the firm of Smith, Jones, Johnson, and Thomas, Inc. Stock transactions arrive at a mean rate of 20 per hour. Each order received by Joe requires an average of 2.5 minutes to process. What is the probability that there will be two or more orders on the premises?

A production manager at Ultra Clean Dishwashing Company is monitoring the quality of the company’s production process. There has been concern relative to the quality of the operation to accurately fill the 16 ounces of dishwashing liquid. A common requirement in this industry shows that the tolerance should be 5% of the expected volume (±5%). The study of the production process returns the process mean (15.8) and standard deviation (0.3). What is the probability of generating a defect?

During the early morning hours, customers arrive at a branch post office at an average rate of 45 per hour (Poisson), while clerks can handle transactions in an average time (exponential) of four minutes each. The average number of customers waiting for service if six clerks are used is

Customers arrive at a suburban ticket outlet at the rate of 14 per hour on Monday mornings. This can be described by a Poisson distribution. Selling the tickets and providing general information takes an average of 3 minutes per customer, and varies exponentially. There is 1 ticket agent on duty on Mondays. What is the average time in the system?

Customers arrive at a suburban ticket outlet at the rate of 14 per hour on Monday mornings. This can be described by a Poisson distribution. Selling the tickets and providing general information takes an average of 3 minutes per customer, and varies exponentially. There is 1 ticket agent on duty on Mondays. What is the average number in line? 

Joe Ferris is a stock trader on the floor of the New York Stock Exchange for the firm of Smith, Jones, Johnson, and Thomas, Inc. Stock transactions arrive at a mean rate of 20 per hour. Each order received by Joe requires an average of 2.5 minutes to process. What is the mean service rate per hour?

A bank of 10 machines requires regular periodic service. Machine running time and service time are both exponential. Machines run for an average of 44 minutes between service requirements, and service time averages six minutes per machine. If operators cost $15 per hour in wages and fringe benefits and machine downtime costs $75 per hour in lost production, what is the optimal number of operators for this bank of machines?