Question 150654
A manufacturer wants to increase the absorption capacity of a sponge.
Based on past data, the average sponge could absorb 3.5 ounces. 
After the redesign, the absorption amounts of a sample of sponges were (in ounces): 4.1, 3.7, 3.3, 3.5, 3.8, 3.9, 3.6, 3.8, 4.0, and 3.9. 
What is the decision rule at the 0.01 level of significance to test if the new design increased the absorption amount of the sponge? 
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Ho: u = 3.5
Ha: u > 3.5
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x-bar of the data = 3.76
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Comment: The decision rule depends on whether you use a "t" or
a "z" critical value.
If "t" the decision rule is "reject Ho if t is above 2.821".
If "z" the decision rule is "reject Ho if z is above 2.326".
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Cheers,
Stan H.