IConfidence Intervals 4. (a) A Fisheries Officer wants to estimate the mean weight of codfish caught on a particular day. She randomly selected 21 codfish caught that day and found the sample mean to be 8.12 kg per fish with a sample standard deviation of 1.85 kg per fish. Construct a 90% confidence interval for the mean weight of codfish caught on that day. Assume the weight of codfish in the population is normally distributed. (b) Using Excel, Formulas, More Functions find (confirm) the Margin of Error for the above confidence interval. Submit your output Note: On the hypothesis testing questions you must use the five-step process outlined in Section 9.4 in our text. Make sure you make a statement at the end of each hypothesis test about the result of your test (ie. Don't just say for example "Reject the null", at the end of your test, you would say something like "Reject the null, therefore the mean salary of doctors in NL is greater than $105,000")