Valtec Electronics fills orders for its electronic components and parts by truck to customers through several distribution centers. A measure of its supply chain responsiveness is order fulfillment lead time, which is the number of days from when a company receives an order to when it is delivered to the customer. A distribution center manager has taken 20 samples of 5 orders each during the month and recorded the lead time for each as follows:

Construct an xˉ-chart to be used in conjunction with an R-chart using 3σ limits for this data and indicate if the process is incontrol.

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