Question

In Exercises 5–8, use the following two control charts that result from testing batches of newly manufactured aircraft altimeters, with 100 in each batch. The original sample values are errors (in feet) obtained when the altimeters are tested in a pressure chamber that simulates an altitude of 6000 ft. The Federal Aviation Administration requires an error of no more than 40 ft at that altitude.

If the R chart and\(\bar x\)chart both showed that the process of manufacturing aircraft altimeters is within statistical control, can we conclude that the altimeters satisfy the Federal Aviation Administration requirement of having errors of no more than 40 ft when tested at an altitude of 6000 ft?

Short answer

A control chart can be used to see if the process mean and the process variation are within statistical control or not;still, they saynothing about the specifications or requirements of the variable under consideration.

Step-by-step solution

Given information

When aviation altimeters are tested in a pressure chamber, the R chart and \(\bar x\)chart are plotted to show the measurement of errors (in feet). The sample size for each individual is 100.

Limitations of control charts, R chart, and \(\bar x\) chart

R chart is a plot that determines the variation present in the statistical process by examining the sample ranges of all the samples varied over time.

\(\bar x\)chart is a plot that determines the central value of the process by examining the sample means varied over time.

Control charts can be used to determine whether the process mean and the process variation are within statistical control or not.

A control chart cannot be used to test whether the process meets certain specifications.

Thus, the given control charts ofthe altimeters cannot determine whether the Federal Aviation Administration’s requirement of having errors no more than 40 ft is satisfied or not.