Problem 51 asks us to determine the area under the curve of the normal distribution in percent for z's between -3 and +3. Here I will use Table A-2 beginning on page 560. At z = -3, p = 0.0013; at z = +3, p = 0.9987.Therefore, the area between z = -3 and z = +3 is 0.9987-0.0013 = 0.9974 or 99.74%. A section explaining how to find probabilities from given z scores starts on page 231.

What is the area under the curve between z = -2 and z = +2?Please explain.