A random sample of 100 observations from a normally distributed population possesses a mean equal to 81.1 and a standard deviation equal to 6.7. Use this information to complete parts a through e below. a. Find a 90% confidence interval for u. (Round to two decimal places as needed.) b. What do you mean when you say that a confidence coefficient is 0.90? O A. A confidence coefficient of 0.90 means that 90% of the values in any sample taken from the population will be contained in an interval estimator constructed using this coefficient. O B. A confidence coefficient of 0.90 means that there is a probability of 0.90 that an interval estimator constructed using this coefficient will enclose the population parameter. O C. A confidence coefficient of 0.90 means that there is a probability of 0.90 that an interval estimator constructed using this coefficient will contain all of the values in the relevant sample. O D. A confidence coefficient of 0.90 means that 90% of the values in the population will be contained in an interval estimator constructed using this coefficient. c. Find a 95% confidence interval for H. (Round to two decimal places as needed.)