A quality manager in a small manufacturing company wants to estimate the proportion of items produced by a very specialized process that fail to meet a customer's specification. Because it is very expensive to determine if an item produced by the process meets the specification, only a very small number of items can be tested. A random sample of 15 items was selected, and in the sample three of them failed. At the 98% confidence level, what is the margin of error in the plus four estimate of p