To compute the margin of error for the 80% confidence interval for u, you will need a critical value from the standard normal distribution. This number, 2c, is the number such that an area equal to c under the standard normal curve falls between zc and 26. Use the table below to find the critical value for a condence level of 80%. Confidence Interval Critical Values zc Level of Confidence c 0.70, or 70% 1.04 0.75, or 75% 1.15 0.80, or 80% 1.28 0.85, or 85% 1.44 0.90, or 90% 1.645 0.95, or 95% 1.96 0.98, or 98% 2.33 0.99, or 99% 2.58 20.80 = :1 Furthermore, you will need to estimate E, the maximal margin of error which can be approximated as Approximate the maximal margin of error, E, by using 25 from above, the given population standard deviation, and the sample size, n Recall that n = 18 and a = 0.37. (Round your answer to two decimal places.) E 0 20.30 V