Use Table A or software. Use Table A or software to find the proportion of observations from a standard Normal distribution that falls in each of the following regions. In each case, sketch a standard Normal curve and shade the area representing the region.

(a) z ≤ −2.10

(b) z ≥ −2.10

(c) z > 1.60

(d) −2.10 < z < 1.60