Assume that yield strength (ksi) for a steel is normally distributed with (sigma)^2 = 4. Assume...

Assume that yield strength (ksi) for a steel is normally distributed with (sigma)^2 = 4. Assume (mu)= 12 What is the yield strength value separates the strongest 6-% from the others? What is the probability that sample mean of yield strength is less than 12.5 for sample size 50? Assume the 99% confidence interval for (mu) is (7.7,9.2), what would be a 90% confidence interval calculated from the same sample size and sample mean? Assume we have a sample set with x(bar)= 11.7, n=50. Decide whether the population mean of yield strength is less than 12? Using a=.02

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Expert Solution

The standard deviation is

What is the yield strength value separates the strongest 6-% from the others?

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What is the probability that sample mean of yield strength is less than 12.5 for sample size 50?

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It is given that 99% confidence interval for (mu) is (7.7,9.2) so

Adding these equations give

The 90% confidence interval is:

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orchestra answered 1 year ago

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