Question

In a manufacturing plant, dowel widths are normally distributed with an average of 5 mm and...

In a manufacturing plant, dowel widths are normally distributed with an average of 5 mm and standard deviation of 0.02 mm. Each hour, a random sample of 25 dowels is taken to ensure that the average width is not significantly different from 5 mm. In one sample, the average was 5.0054 mm.

  1. Why is the Z test the appropriate test for this situation?
  2. Test the hypothesis at a 5% level of significance.
  3. If the level of significance were 7.68%, what conclusion would be reached and why?
  4. If a level of significance had not been specified, what conclusion would be reached and why?

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