Step 5 Converting to the standard normal random variable z, the probability statement P(p 2 0.25) is now P(z 2 -2.16). Recall that the normal probability table gives area under the curve to the left of a given z value. Since we want the area to the right of z = -2.16 and the area under the entire curve is 1, the area to the left of z = -2.16 can be subtracted from 1. Use the table to find the probability that the sample proportion of individuals who will respond to questions on a telephone survey is at least 0.25, P(z > -2.16), rounding the result to four decimal places. P(z 2 -2.16) = 1 - P(z S -2.16) X X