问题
填空题
举行的数学竞赛中，全体参赛学生的竞赛成绩近似服从正态分布N（70，100），已知成绩在90分以上（含90分）的学生有12名，若Φ(2)=0.9772，则此次参赛生总人数约为（ ）。
答案
526
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举行的数学竞赛中，全体参赛学生的竞赛成绩近似服从正态分布N（70，100），已知成绩在90分以上（含90分）的学生有12名，若Φ(2)=0.9772，则此次参赛生总人数约为（ ）。
526
| 从对话后的选项中选择适当的选项补全对话。 | |
| B: Bob D: Doctor D: Come and sit down, Bob. 1______ B: I have a terrible pain in my stomach, doctor. D: I see. When did it start? B: 2______ I didn't want to eat anything. I'm not feeling well now. D: Let me see, er, you have a fever. B: I've got a headache, too. And my throat hurts. D: Well, you've caught a bad cold. B: 3______ D: No, not very serious. But you must stay in bed for 2 or 3 days and take the Chinese medicine. B: 4______ D: Three times a day after meals. B: Thank you. | |
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