Confidence interval for a single mean. one way to determine how banks rate in jobs and productivity is to examine the annual profits per employee. forbes top companies, edited by j. t.davis (john wiley & sons), gave the data as seen in the file profits. jmp about annual profits per employee (in units of one thousand dollars per employee) for representative companies in the financial services. what is the t-value you would use for the 90% confidence interval with this data. only give a number with 3 decimal places. use the proper rules of rounding.