document.write( "Question 899413: A consumer advocacy group suspects that a local supermarket's 500 grams of sugar actually weigh less than 500 grams. The group took a random sample of 20 such packages, weighed each one and found the mean weight for the sample to be 496 grams with a standard deviation of 8 grams. Using 10% significance level, would you conclude that the mean weight is less than 500 grams? Also, find the 90% confidence interval of the true mean. \r
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Algebra.Com's Answer #545383 by ewatrrr(24785) $\"\"$ $\"About$

You can put this solution on YOUR website!

 
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document.write( "Hi
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document.write( "Ho: u ≥ 500
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document.write( "Ha: u < 500
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document.write( "t(496) = (496-500)/[8/sqrt(20)] = 4/1.7889 = 2.236
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document.write( "p-value = P(t> 2.236 when df = 19) = tcdf(2.236,100,19) = .9825
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document.write( "As .9825 > .10,  No, would not conclude mean is <500 
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document.write( "ME = 1.645(8/sqrt(25))
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document.write( "CI: = 496 - ME <  < 496 + ME
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