Homework Section 6.1 1) Find the critical value zc that corresponds to a 98% confidence level. 2) Find the margin of error E for the given values of c = 0.90, o = 11.5, n = 120 3) The standard IQ test has a mean of 96 and a standard deviation of 14. We want to be 99% certain that we are within 4 IQ points of the mean. Determine the required sample size. 4) Consider the confidence interval (19, 27) for the population mean. Find the mean x and the margin of error E. 5) A random sample of 150 students has a grade point with a mean of 2.86. Assume the population standard deviation is 0.78. Construct the confidence interval for the population mean if c = 0.99