An economist is interested in studying the incomes of consumers in a particular region. The population standard deviation is known to be $2,000.

An economist is interested in studying the incomes of consumers in a particular region. The population standard deviation is known to be $2,000. A random sample of 50 individuals resulted in an average income of $30,000. What sample size would the economist need to use for a 95% confidence interval if the width of the interval should not be more than $200?