Question 190959
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. Using α = .05, is the mean weight of all circulated dimes lower than the specification? Explain your decision. 
Hypothesis Test: Mean vs. Hypothesized Value

2.26800 hypothesized value 
2.25600 mean Sample data 
0.02600 std. dev. 
0.00671 std. error 
15 n 
14 df 

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Ho: u = 2.268
Ha: u < 2.268
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test statistic: t = -1.79 t 
p-value = 0.0478 p-value (one-tailed, lower)
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Conclusion:
Since the p-value is lessthan 5%, reject Ho.
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2.24160 confidence interval 95.% lower 
2.27040 confidence interval 95.% upper 
0.01440 half-width 
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Cheers,
StanH.