A study of the survival of small businesses chose an SRS from the telephone directory’s Yellow Pages listings of food-and-drink businesses in 11 counties in central Indiana. For various reasons, the study got no response from 45% of the businesses chosen. Interviews were completed with 145 businesses. Three years later, 21 of these businesses had failed. Give a 92% confidence interval (±0.001) for the percent of all small businesses in this class that fail within three years: ⩽p⩽. Based on the results of this study, how large a sample would you need to reduce the margin of error to 0.04? n = .