Question 4 A quality control engineer at a potato chip company tests the bag filling machine by weighing bags of potato chips. Not every bag contains exactly the same weight. But if more than 19% of bags are over-filled then they stop production to fix the machine. They define over-filled to be more than 1 ounce above the weight on the package. The engineer weighs 110 bags and finds that 31 of them are over-filled. He plans to test the hypotheses $H_0: p = 0.19$ versus $H_a: p > 0.19$. What is the test statistic? $Z = $ (Please round your answer to two decimal places if necessary.)
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Sample proportion (p-hat) = number of over-filled bags / total number of bags p-hat = 31 / 110 p-hat = 0.2818 Show more…
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A potato chip manufacturer produces bags of potato chips that are supposed to have a net weight of 326 grams. Because the chips vary in size, it is difficult to fill the bags to the exact weight desired. However, the bags pass inspection as long as the standard deviation of their weights is no more than 4 grams. A quality control inspector wished to test the claim that one batch of bags has a standard deviation of more than 4 grams, and thus does not pass inspection. If a sample of 21 bags of potato chips is taken and the standard deviation is found to be 5.3 grams, does this evidence, at the 0.10 level of significance, support the claim that the bags should fail inspection? Assume that the weights of the bags of potato chips are normally distributed. Step 1 of 3: State the null and alternative hypotheses for the test. Fill in the blank below. H0: σ = 4 Ha: σ > 4 Step 2 of 3: Compute the value of the test statistic. Round your answer to three decimal places. Step 3 of 3: Do we reject the null hypothesis? Is there sufficient or insufficient data?
Adi S.
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