Final answer:
Marcus initially reported that the error rates were between 18% and 22% with a maximum error bound of ± 3 percent.
Step-by-step explanation:
Marcus initially reported that the error rates were between 18% and 22% based on a confidence interval (CI) with a margin of error of 0.02 (EBM). The ± 3 percent mentioned is the maximum error bound, which means that the reported error rates can be as low as 18% or as high as 22%. Increasing the sample size can help lower the sampling error.