TABLE FROM HOLLINGWORTH Showing rank in each of two mental functions, within a group of fifth grade children, selected for special disability in spelling. The coefficient of correlation obtained is .081. ═══════════════════════╤═══════════════════════╤═══════════════════════ NAME │ MENTAL AGE │ SPELLING ABILITY │ YRS. MOS. │ PER CENT CORRECT │ (STANFORD-BINET) │ LISTS Q AND R (AYRES) ───────────────────────┼───────────────────────┼─────────────────────── RL │ 13 7│ 90.1 JP │ 12 5│ 95.2 HA │ 12 2│ 81.7 MG │ 11 6│ 31.7 LK │ 10 10│ 80.2 SSh │ 10 10│ 77.9 SSc │ 10 9│ 81.8 MS │ 10 9│ 34.1 PJ │ 10 4│ 32.6 HL │ 10 1│ 58.9 RH │ 9 8│ 93.1 MU │ 9 8│ 57.0 BN │ 9 6│ 92.1 HR │ 8 3│ 81.8 ═══════════════════════╧═══════════════════════╧═══════════════════════ If there is in fact perfect correspondence, so that each pupil holds the same rank on the distribution in both functions, a perfect positive correlation is obtained, the _coefficient of correlation_ being expressed as 1.00. If no relationship at all exists between the two functions measured, so that nothing whatever can be predicted of either from knowing about the other, the coefficient of correlation will be 0.00[3] If there exists a perfect negative relationship, so that the person who stands highest in one stands lowest in the other, and so forth through the series, in a perfect inverse standing of all members, then a coefficient of correlation expressed by −1.00 is obtained.