CP Inc. has been using a specific process to produce a special component. Last year, several customers complained about inconsistencies on the ‘weight' of the component. They stated that there were a disproportionately large percentage of components that didn’t meet the required standards. Based on the complaints, at the start of this year the company implemented a 6σ project to improve the process, which ended one week ago.
At the beginning of this year, CP commissioned you to perform a study to find out the validity of the complaints and justify the process’ improvements. Expeditiously, you designed a study based on their knowledge of statistical quality control. First, you obtained information on the prior process performance on ten consecutive hours, in two consecutive days; the information was gathered on December 4 and 5. Also, you gathered the same number of data, in two consecutive days (February 2 and 3), after the improvements were made.
a) Explain if the customers’ complaints were justified.
b) Explain if the 6σ project was needed.