Use Excel to find the critical value of z for each hypothesis test. (Negative values should be indicated by a minus sign. Round your answers to 3 decimal places.)
(a) 2 percent level of significance, two-tailed test.
Critical value of z±
(b) 1 percent level of significance, right-tailed test.
Critical value of z
(c) 5 percent level of significance, left-tailed test.
Critical value of z