Complete parts (a) through (c) below. (a) Determine the critical value(s) for a right-tailed test of a population mean at the a = 0.10 level of significance with 20 degrees of freedom. (b) Determine the critical value(s) for a left-tailed test of a population mean at the a = 0.10 level of significance based on a sample size of n = 10. (c) Determine the critical value(s) for a two-tailed test of a population mean at the a = 0.05 level of significance based on a sample size of n = 17. Click here to view the t-Distribution Area in Right Tail. (a) terit = (Round to three decimal places as needed.)