Math Solutions

[Steps Shown] . Explain, using examples, why conducting a significance test for a claim is always a one-tail test? . the mass of an item manufactured is

Question:

  1. . Explain, using examples, why conducting a significance test for a claim is always a one-tail test?
  2. . the mass of an item manufactured is known to be normally distributed with a standard deviation of 5 grams?
    In a recent survey, 16 items were randomly selected and were found to have a mean mass of 200 grams.
    1. Calculate a 99% confidence intervals for the mean mass of all the items manufactured, assuming that the standard deviation remain at 5 grams.
    2. If we want to estimate the mean with ± 1, 5 grams at 99% confidence level and the standard remains at 5 grams, calculate the least sample size.
      b). A certain electrical item is known to have a life span of 20,000 hours of usage. However, it has been recently redesigned to improve on its life span. A random sample of 49 such items were tested and found to have a mean life span of 22,000 hours with a standard deviation of 4,000 hours.
      Test at 1% level whether the new design has significantly increased the life span.
      Price: $2.99
      Solution: The downloadable solution consists of 3 pages
      Deliverable: Word Document


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