ALL ABOUT STATSSS

The probability notation P(a a) means z-value is above a and P(Z a) or P(Z 2 a). To illustrate, let us consider these examples: 1. Find the proportion of the area between z = -1.25 and 2.19, this can be expressed as P(-1.25 -0.65) = Solution: STEP 1: Draw a normal curve and locate the Z - score and shade. -2 -1 1 3 STEP 2: Locate the corresponding area of the z - score in the z-table. z =-0.65 has a corresponding area of 0.2578 STEP 3: If you are looking for a greater than area, the area in the table is subtracted from 1, therefore, 1.0000 - 0.2578 = 0.7422 , and the P(Z > -0.65) = 0.7422 or 74.22%