Fluctuations in daily observed and estimated mortality rates during three summers (1975, 1976, 1983), France. Fluctuations in daily observed (black) and estimated mortality rates by model with 1 groupa (right column, blue), 3 groupsb (right column, red) and 4 groupsc (right column, green) for minimum (left column, broken blue) and maximum (left column, red) temperatures in France from June through September, 1975, 1976 and 1983. X-axis: days from 1st June to 30th September (122 days). Y-axis: daily mortality rate (deaths/100,000/day). a 1 group: G2; b 3 groups: G2, GMA, GCum1t; c 4 groups: G2, GMA, GCum1t, Gcum1t-2.