How to Solve z‐Score Area Problems Usually there are two tables – the ‘TAIL’
negative table and the ‘OVER HALF’
positive table. REMEMBER: The whole normal curve has an area of 1.0000, and each half is .5000. Tables give the % area starting from the left. “Tail” Problems 
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z ≤ NEGATIVE
Just look up in “tail” table. Example: z ≤ ‐1.19 → “Over Half” Problems 
0.1170 o
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z ≥ POSITIVE Look up the value and subtract from 1 Example: z ≥ 2.41 → 1 – 0.9920 = 0.0080 
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z ≤ POSITIVE
Just look up in “over half” table. Example: z ≤ 2.22 → 0.9868 z ≥ NEGATIVE Look up the value and subtract from 1 Example: z ≥ ‐0.48→ 1 – 0.3156 = 0.6844 “Slice” or “Middle” Problems 
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Look up both Zscores in either table. Subtract (LARGER P‐value – SMALLER P‐value) to get answer. DO NOT subtract Zscores. 
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POSITIVE ≤ Z ≤ POSITIVE Example: 1.23 ≤ z ≤ 2.34 
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→ (between two positive numbers) 0.9904 – 0.8907 = 0.0997 NEGATIVE ≤ Z ≤ NEGATIVE Example: ‐1.91 ≤ z ≤ ‐0.34 → (between two negative numbers) 0.3669 – 0.0281 = 0.3388 NEGATIVE ≤ Z < POSITIVE Example: ‐2.11 ≤ z ≤ 1.22 → (between a negative and a positive) 0.8888 – 0.0174 = 0.8714