Quality eLine Newsletter
September 2004
Vol. 6, No. 9

Quality Quiz

Professor Cleary's Quality Quiz is the most-frequently-visited feature of the PQ Systems Quality eLine each month.

Once again Marge Orrine (nee Marge N. Avera) is pursuing an undaunted quest for Black Belt, in spite of setbacks and small misunderstandings (as we saw last month, this included understanding the meaning of "average"). She wants to save Natural Dairy Products money and be the first woman Black Belt in her organization.

Now that she understands central location (mean, median, mode) and variability (standard deviation), she has a firm basis for further learning about the shape of distributions and the meanings of those shapes.

Using the 50 data points related to the weight of butter packages--data that she had collected and used to further her understanding of variability--Marge begins by creating a histogram of the weights in order to respond to her department head’s question about skewness of the data.

Miles Aweigh, Marge's boss, comments that the histogram reveals a skewness of -.4. Marge interprets this observation as a sign that the data has been entered wrong and the histogram is therefore somehow flawed. She sets out to change the data slightly in order to correct what she perceives as a defect, and make it come out right. Is she correct?



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