A Car Mechanic Is Thinking of Guaranteeing Customers That an Oil

question 108

Essay

A car mechanic is thinking of guaranteeing customers that an oil change will take no more than 15 minutes with a 99.73% confidence level.He takes a few samples of size 5 and finds the process mean to be 13 minutes with a standard deviation of .2 minutes and average sample range of 1.2 minutes.Find the , ,and values and use them to compute the upper and lower limits for an x-bar chart.Use the upper limit to determine if the mechanic can offer a 15 minute guarantee.Assume the mechanic plots the samples on the x-bar control chart and finds the process is in control,is there anything else the mechanic is missing to ensure the process is in control?

---

Definitions:

Marginal Analysis

An examination of the added benefits of an activity compared to the added costs incurred by that same activity.

Cell Phones

Portable electronic devices that allow users to make voice calls, send text messages, and access various digital services.

Total Profit

The total income a business earns after subtracting all expenses and costs associated with its operations.

Marginal Benefit

The added value or enjoyment a consumer gets from using an additional unit of a product or service.