Suppose that an accounting firm does a study to determine the time needed to complete one person's tax forms. It randomly surveys 175 people. The sample mean is 22.4 hours. There is a known population standard deviation of 6.6 hours. The population distribution is assumed to be normal. Which distribution should you use for this problem? (Round your answers to two decimal places.) X ~ N , Explain your choice. The Student's t-distribution should be used because the sample mean is smaller than 30. The standard normal distribution should be used because the mean is given. The standard normal distribution should be used because the population standard deviation is known. The Student's t-distribution should be used because the sample standard deviation is given