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 15 degrees of freedom. (b) Determine the critical value(s) for a left-tailed test of a population mean at the a = 0.05 level of significance based on a sample size of n = 20. (c) Determine the critical value(s) for a two-tailed test of a population mean at the a = 0.10 level of significance based on a sample size of n = 19. Click here to view the t-Distribution Area in Right Tail. . . . (a) tcrit = (Round to three decimal places as needed.)To test Ho: H = 60 versus H1 : H