In: Math
In a random sample of 85 automobile engine crankshaft bearings, 10 have a surface finish that is rougher than the specifications allow.
1. Construct a 95% two-sided confidence interval for the true proportion of bearings in the population that exceeds the roughness specification.
2. How large a sample is required if we want to be 95% confident that the error in using the sample proportion to estimating the ture value p is less than 5%?
3. How large must the sample be if we wish to be at least 95% confident that the error in estimating the true proportion is less than 5% regardless of the true value of P ?