Concrete cubes are used to test the quality of mix from a concrete mixing plant. 28 day compressive strength is taken as the standard measure to test the quality of the mix. Tests show that mean compressive strength of a sample of cubes is 28.4 units with a standard deviation of 2.95 units. To assure quality, the mixing company requires that at least 95% of the samples have compressive strength greater than 24 units. Based on this information and assuming a large sample size, answer the following questions. After major improvements on the plant, the mixing company is able to make cubes more consistent (reduce SD of compressive strength but maintain the same mean). For what value of the new SD will be cube standards be just met? Based on the requirements, only about___% of the samples meet the company standards.?
Concrete cubes are used to test the quality of mix from a concrete mixing plant. 28 day compressive strength is taken as the standard measure to test the quality of the mix. Tests show that mean compressive strength of a sample of cubes is 28.4 units with a standard deviation of 2.95 units. To assure quality, the mixing company requires that at least 95% of the samples have compressive strength greater than 24 units. Based on this information and assuming a large
After major improvements on the plant, the mixing company is able to make cubes more consistent (reduce SD of compressive strength but maintain the same mean). For what value of the new SD will be cube standards be just met?
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