o******6
发帖数: 538 | 1 ☆─────────────────────────────────────☆
lihao (思君) 于 (Wed Feb 13 12:51:02 2008) 提到:
I don't know that much stat at all.
now I need to draw 10 simple random sample from a population N=600.
and I need calculate mean for each of those sample.
here is a example data and code I have so far.
draw 5 samples sample size=7 from this population n=9.
and how to calculate the mean for each sample?(with replacement)
data math;
input teid i1c1 i1c2;
cards;
001 1 2
002 2 3
003 3 4
004 0 1
005 2 2
006 2 |
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a********a
发帖数: 346 | 2 不明白在mixed model 中random effect and repeated 的区别，请高人指点一下。 |
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D******n
发帖数: 2836 | 4 They control different things, should check the mathematical model that
MIXED uses from the SAS documentation, it is very clear. But, as far as my
experience is concerned it is not very straightforward to see what effect
will be generated by using certain parameter combination of random and
repeat, u have to "figure" it out. |
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o******6
发帖数: 538 | 5 ☆─────────────────────────────────────☆
Chinanan (nanan) 于 (Mon Feb 16 23:30:19 2009) 提到:
自己尝试了一些办法，但是问题没得到解决，所以上来请教一下各位：
从200个community中sample了大约5000个household，每个household中又有若干
individual，对于这些individual做了4个wave的repeated measurement，最后的结果
是有大约47000个individual repeated measurements。
dependent variable是binary的，所以试图用random-effects model with varying
intercepts来handle三个level的correlation：
(1)within-individual correlation due to repeated measurements over time(4
waves);
(2)within-household correl |
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h******e
发帖数: 1791 | 6 用sas generate random number时，这个seed是起什么左右的？ |
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z**k
发帖数: 378 | 7 可以。ranuni(0)表示seed也是random的，你担心的太多了。 |
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p*****o
发帖数: 543 | 8 I HAVE AN ORIGINAL DATA SET WITH VARIABLE: ID，AND THE DATA SET LOOKS LIKE:
ID
1_A
1_B
1_C
1_D
2_A
2_B
2_C
2_D
.....
.....
100_A
100_B
100_C
100_D
我现在只需要一半的数据(RANDOMLY SELECTED), 但问题是，如果选择了1_A,那么 1_B,
1_C 还有 1_D 也必须被选上?
试了PROC SURVEYSELECT，但是不知道如何处理这个问题，请大侠赐教！！
THANKS A LOT!! |
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p*****o
发帖数: 543 | 9 could you tell me a little bit more....
which procedure? proc surveyselect? how could i only random sampling the
numbers?
thanks a lot |
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p*****o
发帖数: 543 | 10 thanks a lot!!
randomly
1,...,
merge |
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j******1
发帖数: 62 | 11 Below is the problem.
A multi-site agricultural experiment is being planned in which several
varieties of a given crop are going to be allocated to plots within each
site using a randomized complete-block layout. The sites have been chosen
to differ dramatically over the range of the environments in which the crop
is grown. Varietal differences are not expected to homogeneous over the
sites, and the best performing varieties at some locations are not expected
to be the best performing varieti |
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s******y
发帖数: 522 | 12 要做一个关于老年人的课题，但现有的数据库是对于全部年龄群的采样
如果从中把所有的老年人样本删选出来，这样还是randomized的吗 |
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j*****e
发帖数: 182 | 13 How did you sample from the pop with all ages?
What about the sample size of elderly?
Randomized means iid. Are subjects iid here? |
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p***r
发帖数: 920 | 14 there is no sample is randomized, every sample is fixed, after you stick
with a design. |
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m*******7
发帖数: 244 | 15 What are the differences between random effect model and GEE? |
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x*******i
发帖数: 1791 | 17 random effect model阿。
你这问题问的。。。 |
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d*******1
发帖数: 854 | 18 我有一个DATASET， 大概10万个数据点。 想用PROC SURVEYSELECT 取样10000 （with
replacement)， 目的是确保取样和原始数据是一样的分布。请问用什么OPTION 在
SURVEYSELECT里。 因为我知道最简单的RANDOM SAMPLING 每个data point 被选的几率
是一样的。 |
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D******n
发帖数: 2836 | 19 fts.....
if u randomly sample data from a population, it asymptotically follow the di
stribution of that population.
with |
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y******r
发帖数: 37 | 20 Hello;
in sas, how do you randomly pick 10 numbers out of 29? |
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a********e
发帖数: 78 | 21 这个random sequence由3000 个点组成，符合normal distribution， mean 是 c,
standard deviation 是d.
但这3000 个点 都落在[a,b]的范围里。
请问应该怎么做，
假如画图的话，y 轴应该是这3000个点， 那x轴的点如何产生？ |
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j******n
发帖数: 2206 | 22 I use this formula
random_number=int(ranuni(0)*100000);
but it will give me 0, I don't want 0. if I add 1 to this formula,the
integer range will be 1 to 100001, which is alo not what I want.
I want exactly random integer numbers ranging from 1 to 100000.
Does anybody have an idea? |
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j******n
发帖数: 2206 | 23 another one:
PROC PLAN can produce a random permutation of the values 1-100000;
there will be no zero.
proc plan seed=1091883594;
factors r=100000 / noprint;
output out=r;
run;
proc print data=r(obs=100);
run;
proc print data=r(where=(r=0));
run; |
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p********a
发帖数: 5352 | 24 Then what is the best way to get random numbers between 1 and N? |
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a****3
发帖数: 11741 | 25 请教如何求解confidence interval of a random sample from gamma distribution?
万分感谢！ |
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s******n
发帖数: 134 | 26 how to use sas to obtain a random sample of size 1000 from f(x,y)=c(c is a
constant) where and 0
Help!! Thanks a lot~~ |
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D******n
发帖数: 2836 | 27 random x,y, and then reject those violate the conditions |
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p********a
发帖数: 5352 | 28 ☆─────────────────────────────────────☆
jingjuan (hi) 于 (Sun Sep 12 16:53:32 2010, 美东) 提到:
I use this formula
random_number=int(ranuni(0)*100000);
but it will give me 0, I don't want 0. if I add 1 to this formula,the
integer range will be 1 to 100001, which is alo not what I want.
I want exactly random integer numbers ranging from 1 to 100000.
Does anybody have an idea?
☆─────────────────────────────────────☆
DaShagen (Unbearable lightness) 于 (Sun Sep 12 17:14:27 2010, 美东) 提到:
0<=ranu |
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a****m
发帖数: 693 | 29 比如说，一个5X5 matrix,
里面有7个1， 8个-1， 其余的为0，
matlab里面有不同的distribution random generator, 但是没有上面说的。
谢谢 |
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a****m
发帖数: 693 | 30 谢谢各位，
是关于random network, 1, -1 0 represent activate inact, no effect.
randperm 仅仅产生一个区间的数，但是没法控制多少个1 -1和0？
3x |
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y*****y
发帖数: 98 | 31 the mechanism of randomness is unclear from your statement. it looks like a
discrete graphical model. zero entries of precision matrix correspond to the
conditional independence. |
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s******a
发帖数: 184 | 32 用accept/rejection method 产生 random sample，
发现对有些分布拟合得很好，对有些就不好，这有规律可循吗？ |
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r*****l
发帖数: 457 | 33 哪位老大来通俗的解释一下
fixed effect 和 random effect的区别啊。半路出家，老被别人问，自己却讲不清楚 |
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a****m
发帖数: 693 | 34 fixed refers to the specific variable which you studied in your experiment.
random means a sample from a population, which you can not sample one by one
, but you can take one as representative. |
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r*******e
发帖数: 510 | 35
experiment.
one
就是这样的。RANDOM 只影响方差，不影响均值 |
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D*********2
发帖数: 535 | 36 俺伺候过一任老板，自由度不够的时候就把fix换random... |
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d**********r
发帖数: 24123 | 37 同赞。个人的理解是 Fixed Effects 是俺选取的，而Rabdom 不是自己控制的。
比如天气。
如果你专门选择晴天和雨天来做，那么这个天气就是Fixed。
如果你不专门挑选晴雨，碰到什么就是什么，那么这个天气就是Random |
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F****n
发帖数: 3271 | 38 I don't think what you say has anything to do with fixed / random effects.
1. 如果你专门选择晴天和雨天来做，-- That only means your population is only
晴天 + 雨天 because you are particularly interested in contrasting these two
groups. Your results will only reflect the variation between these two.
2. 如果你不专门挑选晴雨，碰到什么就是什么 -- That means you are modeling the
entire population. |
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H**********v
发帖数: 169 | 39 One thing you want to keep in mind is that random effect is introduced into
the fixed effect model to solve the problem with independent observations,
so the off-diagonal elements in a variance-covariance matrix don't have to
be all zeros. It will help if you read something about hierarchical linear
model and variance component. |
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s****e
发帖数: 1180 | 40 完全和normality无关，就是两个random variables，分布类型完全不同，也都不是
normally distributed， 一个来自poisson分布，一个来自binomial分布，他们之间的
correlation怎么刻画？ |
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f***c
发帖数: 301 | 41 最简单的比如 Yi= a + bXi + ei
这样一个线性模型 如果假设 Xi 也是一个random variable,服从正态分布不知道mean
和variance, 怎么estimate a,b还有X的mean,variance，用ML可以么
找了找相关的文献 似乎有人把这个算作measurement error model可是又没有讲怎么
estimate,希望有人可以指点一下 谢谢 |
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f***c
发帖数: 301 | 42 十分谢谢回复！！
我也咨询了下econometrics的老师 实际X也是random term 但是我们能够观察到X的值
可不可以这样理解 在一般的假设中 如果观察到的x值和实际值有偏差 比如实际值是x+
error, 那么这个error已经被e考虑到了 |
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h*********t
发帖数: 147 | 43 是的。
但是和其他random factor有不同。 |
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B****k
发帖数: 188 | 44 What do you mean by saying "random"? Do you mean it has no pattern?
If so, the Null could be "the overlapping have the same distribution with
group A (or B)". |
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D******n
发帖数: 2836 | 45 well if u say so, but what you are asking is still not clear.
random
A
probability |
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t****a
发帖数: 1212 | 46 You can use fisher exactly test to tell if the overlapping is random. Before
doing this you need to now that the size of the background (the DaShagen's
questions: How many genes are there?). In the following code I just assumed
the background size is 20000, both A and B are sampled from the background.
# R code here.
bg <- 20000; a <- 3000; b <- 4000; ab <- 500
your.data <- matrix(c(ab, a-ab, b-ab, bg-a-b+ab), 2, 2)
colnames(your.data) <- rownames(your.data) <- c('In Group', 'Not In Group')
name... 阅读全帖 |
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a*****t
发帖数: 28 | 47 hello everyone
There is anyone can tell me how to generate bivariate random sample base on
the density function( given), by using SAS or other software.
Thank you |
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b********n
发帖数: 162 | 48 如果先生成一个Gaussian Random Field,经过转换后，covariance function就变了，
那range也变了。
没有搜到有简洁的方法可以实现的，难道要自己写code。 |
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a***e
发帖数: 1627 | 49 A production engineer wishes to study the effect of cutting temperature and
cutting pressure on the surface finish of the machined component. He designs
an experiment wherein three levels of each factor are selected, and a
factorial experiment with two replicates in run. The relevant data in
certain standard units are given as follows.
Temperature
Pressure Low Medium High
Low 51.5 51.8 51.3
51.3 51.7 51.5
Medium 51.2 51.6 4... 阅读全帖 |
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g***l
发帖数: 22 | 50 Fixed effect。这里两个variable每一个都有三个level，这些都是固定的。random
effect一般用来构造hierarchical model来处理一些lurking variables，允许对于不
同的level有不同的variance，这里不存在的。
and
designs |
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