A researcher wishes to estimate the proportion of X-ray machines that malfunction. A random sample of 200 machines is taken, and 70 of the machines in the sample malfunction. Based upon this, compute a 90% confidence interval for the proportion of all X-ray machines that malfunction. Then find the lower limit and upper limit of the 90% confidence interval. Carry your intermediate computations to at least three decimal places. Round your answers to two decimal places. (If necessary, consult a list of formulas.) Lower limit: X ? Upper limit