The representative sample selected for a mail survey of businesses had the following distribution of types of firms: 20% industrial-goods manufacturers, 30% consume goods manufacturers, 25% retailing firms, and 25% service firms. A total of 1000 questionnaires were mailed, but responses were obtained only from 280 firms, consisting of 65 industrial-goods manufacturers, 75 consumer goods manufacturers, 55 retailing firms, and 85service firms. Assuming that the type of firm is likely to have a major bearing on the questionnaire responses, can one be 99% confident that there was no significant nonresponse error?