=+14.5 ▼ The article “The Influence of Temperature and Sunshine on the Alpha-Acid Contents of Hops” (Agricultural Meteorology [1974]: 375–382) used a multiple regression model to relate y 5 yield of hops to x1 5 mean temperature (8C) between date of coming into hop and date of picking and x2 5 mean percentage of sunshine during the same period. The model equation proposed is