Situation Paula is an engineer for a company that specializes in the production of filters for many industrial applications. One of the primary components of the filters is the media. The media is the fibrous material inside a filter, which actually does the job of filtering. Paula’s job is to make sure that the media is produced according to the specifications. The media for each specific type of filter is made on a continuous process. Coils of media are cut to a length specified by the process. The media must meet several critical requirements. One of these requirements is the thickness of the media. As each coil of media is completed, the thickness is measured in three places across the coil. As long as these values meet specifications, no questions are asked. Otherwise, Paula initiates an investigation to determine the cause of the out-of-specification values. After attending a class on statistical process control, Paula decided to make a process behavior chart with the thickness data. Available Data Thickness values for 20 consecutive coils of media are given in the table, “Media Thickness Data.” Specifications for media thickness are 12.5 ± 1.5. Questions 1. Paula set up an average and range chart for the thickness data using a subgroup of size n=3. Construct such a chart using the data provided and interpret the results of this analysis for her. 2. If Paula wanted to determine the behavior of media thickness from roll to roll, how should the data be organized on a process behavior chart? 3. Is this process meeting the specifications for media thickness? What could Paula predict for media thickness?
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