K Which distribution should be used to construct the confidence interval Use the standard normal distribution or the t distribution to construct a 90 confidence interval for the population mean Justify your decision If neither distribution can be used explain why Interpret the result In a random sample of 12 mortgage institutions the mean interest rate was 3 54 and the standard deviation was 0 38 Assume the interest rates are normally distributed OA The 90 confidence interval is point s possible BID OA Use a normal distribution because the interest rates are normally distributed and a is known OB Use a t distribution because the interest rates are normally distributed and a is known OC Use a t distribution because it is a random sample o is unknown and the interest rates are normally distributed OD Use a normal distribution because n 30 and the interest rates are normally distributed O E Cannot use the standard normal distribution or the t distribution because a is unknown n 30 and the interest rates are not normally distributed Select the correct choice below and if necessary fill in any answer boxes to complete your choice Round to two decimal places as needed OB Neither distribution can be used to construct the confidence interval Interpret the results Choose the correct answer below quiz OA With 90 confidence it can be said that the population mean interest rate is between the bounds of the confidence interval OB It can be said that 90 of institutions have an interest rate between the bounds of the confidence interval OC If a large sample of institutions are taken approximately 90 of them will have an interest rate between the bounds of the confidence interval nco interval