A normal distribution of data has a mean of 90 and a standard deviation of 18. What is the approximate z-score for the value 64?

Use the z-score formula: z = (value − mean) ÷ standard deviation. For 64, z = (64 − 90) ÷ 18 = −26 ÷ 18 ≈ −1.4. Therefore, the approximate z-score is –1.4, choice B.

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