Use the standard normal distribution or the t-distribution to construct a 95% confidence interval for the population mean. Justify your decision. If neither distri can be used, explain why. Interpret the results. In a random sample of 19 mortgage institutions, the mean interest rate was 3.43% and the standard deviation was 0.43%. Assume the interest rates are non distributed. Which distribution should be used to construct the confidence interval? OA. Use a normal distribution because n< 30 and the interest rates are normally distributed. DB. Use a t-distribution because it is a random sample, o is unknown, and the interest rates are normally distrihutod