Variability is often considered to be the enemy of efficient and effective management. One approach to managing cycle times to improve delivery dependability is to map out the associated activities in a value$-$added process using a process flow diagram $($see diagram in problem below$).$ This allows the manager to identify and measure the specific activities so that the management process can be made

Problem

Company X has recently completed an analysis of its primary value$-$added process. As part of this analysis, the major flows have been mapped such that the process has been broken down into $10$ major activities. To better understand the process, the times to complete each of these activities have been carefully monitored over the past month. The results of this monitoring follow.

Develop a $95$ percent confidence interval for the process.