Exercice1 : Lors d’un match de foot, un joueur a passé le tiers de son temps assis sur le banc des remplaçants, puis les
¾ du temps restant à s’échauffer. Il jouera le temps restant.
1) Déterminer la fraction correspondant à son temps de jeu.
2) Sachant que le match dura 90 minutes, quel durée a-t-il joué ?

Researchers are conducting experiments to determine the role of alcohol in the development of depression. after the study is complete, they determine that the relative risk of developing depression is 1.55 with a 95 % ci of 1.2 -1.9. each group is then divided into nonsmokers and smokers. the relative risk for the nonsmokers is 1.12 with a 95% ci of 0.87-1.37. the relative risk for the smokers is 1.7 with a 95 % cl of 1.5-1.9. what type of bias may affect this study? a. procedure bias b. recall bias c. selection bias d. confounding e. lead-time bias