问题
单项选择题
设连续型随机变量X的分布函数,密度函数为f(x),则f(x)=()。
A.
B.
C.
D.
答案
参考答案:B
解析:
由分布函数与密度函数的关系F’(x)=f(x)得
设连续型随机变量X的分布函数,密度函数为f(x),则f(x)=()。
A.
B.
C.
D.
参考答案:B
解析:
由分布函数与密度函数的关系F’(x)=f(x)得
信息归纳。请仔细阅读,按信息表中的项目要求填写信息。 In today’s fast –paced(快步伐/节奏的)culture, many people may feel like they ‘re too busy to read a book. In fact, a recent survey found that reading rates (比率)are falling in the US. Young people in particular(特别的)are more likely to spend their free time watching TV or surfing the Internet than reading a novel or nonfiction(非小说类文学作品)book. According to the survey results, the average(平均) 15 to 24-year-old living in the US spends 2 hours per day watching TV, and only 7 minutes reading for pleasure. Considering all the high-tech forms of entertainment out there, from video games to cyberspace(赛博空间), maybe it’s not surprising that fewer people read these days. But is reading just an old-fashioned pastime, or is it a lost art? Marni,an office worker, said, ”I’m reading the most incredible(不可思议的) book right now, and I can’t even imagine not having that in my life, like not loving reading.” What ‘s your opinion? Information Card
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