PROBLEM $11-22$ Internal Business Process Performance Measures $[$L$03]$

Exeter Corporation has recently begun a continuous improvement campaign. As a consequence, there have been many changes in operating procedures. Progress has been slow, particularly in trying to develop new performance measures for the factory.

Management has been gathering the following data over the past four months:

$\backslash$table$[[,$Month$],[,1,2,3,4],[$Quality control measures:$],[$Customer complaints as a percentage of units sold.,$1\mathrm{.}4\%,1\mathrm{.}3\%,1\mathrm{.}1\%,1\mathrm{.}0\%$