登录
  • #数学|统计

求1‌‌‌‌‌‌‍‍‌‍‍‌‌‍‌‍‌‍‍‍‍‌‌‍‍‍‍‍‍‌‌‌-1统计tutor(有偿)

enennnnnn
320
1
最近在准备DS面试,但是我统计真的很差,看面经有时候答案都看不懂,就想问问有没有统计大神愿意跟我一起go through一下面经题。对于懂的人来说应该不难,我主要的问题就是什么时候该用什么distribution,以及下面这两段我都看不懂。我真的很想补一下。可以付$50一小时(可商量)有时间有兴趣的朋友可以联系我 participant024@gmail.com

1) 一共有N个conference room from no.1 to no.N。有K个meeting独立随机分配到这N个 conference room。现在已知1号conference room里面被schedule了一个meeting,问1 号conference room里面被schedule的总共的meeting的数量(已知1号房存在一个 meeting,也就是1号房不为空。在这个条件下求1号房总的meeting数的期望。把 meeting的集合写成 M1,M2,...,Mk,对任意的i, 利用Bayes公式计算条件概率)

4) estimate distribution of number of payments in a month (x轴是number of payments, y是

number of users); 求这个distribution的mean和median, 是不是 会有偏差? distribution with a long right tail / right skewed distribution

* 指数分布不行,因为是连续的

* 泊松分布:方差和平均数必须一样(the probability of a given number of events occurring in a fixed interval of time or space. If these events occur with a known constant mean rate and independently of the time since the last event)

* zero inflated negative binomial: modeling count variables with excessive zeros and it is usually for overdispersed count outcome variables. Furthermore, theory suggests that the excess zeros are generated by a separate process from the count values and that the excess zeros can be modeled independently.
1条回复
热度排序

发表回复