The CIO of a major company is studying the use of the company's email service for non-business communications, which is against company policy. The CIO wants to estimate the proportion of email messages that are non-business related and she wants to be within 5% of the actual proportion. A previous study indicated that approximately 30% of employee email is not business related. How large a sample should the CIO take if she wants to be 98% of confident of the result?

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