Suppose the length, in words, of the essays written for a contest are normally distributed and have a known population standard deviation of 325 words and an unknown population mean. A random sample of 25 essays is taken and gives a sample mean of 1640 words. Identify the parameters needed to calculate a confidence interval at the 98% confidence level. Then find the confidence interval. z0.10 z0.05 z0.025 z0.01 z0.005 1.282 1.645 1.960 2.326 2.576 You may use a calculator or the common z values above. Round the final confidence interval endpoints to the nearest whole number.