In countryA, the vast majority(90%) of companies in the chemical industry are ISO 14001 certified. The ISO 14001 is an international standard for environmental management systems. An environmental group wished to estimate the percentage of countryB's chemical companies that are ISO 14001 certified. Of the 550 chemical companiessampled, 385 are certified.

a) What proportion of the sample reported beingcertified?

b) Create a 90% confidence interval for the proportion of countryB's chemical companies with ISO 14001 certification.(Be sure to checkconditions.) Compare to the country A proportion.