Quality Control

Writing Assignment 6

Quality Control

You are in charge of making sure boxes of widgets have the correct average weight.

The weight of the widgets are normally distributed, with the mean weight of one widget being 25 grams, and the standard deviation 2 grams.  You must determine the minimum number of widgets that should be put into each box to guarantee that there is a 99% chance that the mean weight of a widget in each box is within 0.5 gram of 25 grams.  Explain how you derive your answer.

Due to consumer complaints, a new company directive demands that there is a 99.9% chance that the mean weight of a widget in each box is within 0.5 gram of 25 grams.  How many widgets now must be put into each box?

Use Excel (=NORM.S.INV) to compute the critical  values, and incorporate the output into your paper.  Calculations for n, the number of widgets, may be done either in Excel or by hand in your paper, but the cells you use in Excel should be copied onto your Word document.

The assignment should be about one page long, plus the Excel output, using 12-point Times New Roman font, 1-inch margins, and 1.5 line spacing.  (Click on Page Layout, Paragraph, “1.5 lines” under “Line spacing”.)

Grading:

• Content (6 points) Student should answer all the questions, with a paragraph for each question.
• Conventions of language (2 points)

The assignment should be written using clear complete sentences.  There should be no spelling or grammar errors, and you should use Spell-check. (Click Review, then “Spelling & Grammar”.)

• Mechanics (2 points) The Excel output, properly labeled, should be incorporated in appropriate places in the document. The assignment should be written using clear complete sentences.  There should be no spelling or grammar errors, and you should use Spell-check. (Click Review, then “Spelling & Grammar”.)

Feel free to allow the Campus Writing Center in L-118 to guide you.  Take a copy of the assignment with you when visiting the Writing Center.