Question 177279: A U.S. dime is supposed to weigh 2.268 grams. A random sample of 15 circulated dimes showed a mean weight of 2.256 grams with a standard deviation of .026 grams.
9.55 A U.S. dime is supposed to weigh 2.268 grams. A random sample of 15 circulated dimes showed a mean weight of 2.256 grams with a standard deviation of .026 grams.
(a) Using α = .05, is the mean weight of all circulated dimes lower than the specification? State your hypotheses and decision rule.
(b) Why might circulated dimes weigh less than the mint specification? (See Science News 157, no. 14 [April 1, 2000], p. 216.)
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A U.S. dime is supposed to weigh 2.268 grams. A random sample of 15 circulated dimes showed a mean weight of 2.256 grams with a standard deviation of .026 grams.
9.55 A U.S. dime is supposed to weigh 2.268 grams. A random sample of 15 circulated dimes showed a mean weight of 2.256 grams with a standard deviation of .026 grams.
(a) Using α = .05, is the mean weight of all circulated dimes lower than the specification? State your hypotheses and decision rule.
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Ho: u = 2.268
Ha: u < 2.268
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If the test statistic is less than -1.645, reject Ho.
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(b) Why might circulated dimes weigh less than the mint specification?
Because of wear and tear on the coins.
Cheers,
Stan H.
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