A standard score indicating the number of standard deviations above or below the mean is called a:

A standard score indicating the number of standard deviations above or below the mean is called a:

Options:

(a) T score

(b) Z score

(c) stanine score

(d) percentile rank

✅ Correct Option: (b) Z score

Explanation (200+ words):

A Z score is a statistical measure that expresses how far a score deviates from the mean in units of standard deviation. It indicates the position of an individual score relative to the population mean. Positive Z scores indicate values above the mean, negative scores below. Z scores are essential for comparing results across different tests and scales, making them a common concept in research methodology. Unlike percentile ranks, which show relative standing, Z scores provide standardized distances. T scores and stanines are derived from Z scores but use different scales. Understanding Z scores is critical for PPSC exams, particularly in educational measurement and assessment.

10 Related Facts:

Z score = (X – mean)/SD Standardized score Positive = above mean Negative = below mean Useful for comparisons Basis for T scores Basis for stanine scores Shows deviation from mean Common in psychometrics PPSC assessment questions frequently use Z scores.