Use a t-table, software, or a calculator to estimate the following critical values. a) The critical value of t for a 98% confidence interval with df=12. b) The critical value of t for a 90% confidence interval with df=69. Click the icon to view a t-distribution table of critical values. a) What is the critical value of t for a 98% confidence interval with df=12? (Round to two decimal places as needed.)