a. Calculate the point estimate of the population proportion of successes. (Do not round intermediate calculations. Round your answer to 3 decimal places.) Point estimate b. Construct an 99% and a 90% confidence interval of the population proportion. (Round your intermediate calculations to 4 decimal places, "z" value to 2 decimal places, and final answers to 3 decimal places.) Confidence Level Confidence Interval 99% to 90% to c. Can we conclude at 99% confidence that the population proportion differs from 0.680? No, since the confidence interval contains the value 0.680. Yes, since the confidence interval does not contain the value 0.680. Yes, since the confidence interval contains the value 0.680. No, since the confidence interval does not contain the value 0.680. d. Can we conclude at 90% confidence that the population proportion differs from 0.680? Yes, since the confidence interval does not contain the value 0.680. No, since the confidence interval contains the value 0.680. Yes, since the confidence interval contains the value 0.680. No, since the confidence interval does not contain the value 0.680.