YATES’S CORRECTION An adjustment proposed by Yates (1934) in the chi-square calculation for a 2 × 2 table that brings the distribution based on discontinuous frequencies closer to the continuous chi-square distribution from which the published tables for testing chi-squares are derived.

YEARS OF POTENTIAL LIFE LOST (YPLL) See potential years of life lost.

YIELD The number or proportion of cases of a condition accurately identified by a screening test.

Yoga: An ancient practice that strengthens and tones muscle, improves balance and flexibility, while increasing blood flow and vitality. While there are six distinct forms of yoga, most involve physical movements and holding of postures, while incorporating breathing and mindful attention. Many of the yoga studios incorporate a blend of yoga styles and offer a variety in levels of rigor.