An article in Journal of Structural Engineering presents the results of an experiment that evaluated a...

An article in Journal of Structural Engineering presents the results of an experiment that evaluated a standard method for estimating the brace force for a truss. In a sample of 360 short test trusses the method underestimated the force for 45 of them, and in a sample of 400 long test trusses, the method underestimated the force for 60 of them. Find a 95% confidence interval for the difference between the underestimation rates for long and short trusses.

Expert Solution

Population 1 = long test trusses

Population 2 = short test trusses

Therefore, based on the data provided,95% confidence interval for the difference between the underestimation rates for long and short trusses. p1−p2 is −0.024<p<0.074, which indicates that we are 95% confident that the true difference between population proportions is contained by the interval (-0.024, 0.074)

orchestra answered 2 years ago

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