Skip to main content

All Questions

1 vote
2 answers
56 views

How does the result $\dfrac{1}{n^T} \dfrac{T!}{\prod_{i = 1}^n Y_i!}$ tell us what distribution $T(\mathbf{Y})$ is?

This follows on from my question here. I have the following problem: Let $Y_1, \dots, Y_n$ be a random sample from a Poisson distribution $\text{Pois}(\lambda)$. Recall, the $\text{Pois}(\lambda)$ ...
The Pointer's user avatar
  • 2,096
3 votes
1 answer
241 views

Why is $T(X) = X_{1} + ... + X_{n}$ a sufficient statistics for Poisson $\lambda$ instead of $\frac{1}{n}\sum{X_{i}}$

From Wikipedia: If $X_{1},\dots, X_{n}$ are independent and have a Poisson distribution with parameter $\lambda$, then the sum $T(X) = X_{1} + ... + X_{n}$ is a sufficient statistic for $\lambda$. ...
dariober's user avatar
  • 4,754
1 vote
1 answer
969 views

Sufficient statistic for the distribution of a random sample of Poisson distribution

Let $X_1,...,X_n$ be a random sample from a Poisson distribution with mean $\lambda$ and $T = \sum_{i=1}^n X_i $ . Show that the distribution of $X_1,...,X_n$ given T is independant of $\lambda$ so ...
outofthegreen's user avatar
2 votes
1 answer
283 views

Reparametrization and its effect on sufficient/complete/minimal statistics

Suppose $X_1 \sim Pois(\lambda_1), X_2 \sim Pois(\lambda_2), X_3 \sim Pois(\lambda_1+\lambda_2)$. Separately I can find a sufficient, complete and minimal statistic for each of them. But considering ...
Maverick Meerkat's user avatar
3 votes
1 answer
1k views

Sufficient statistic for poisson

Possion have mean and variance of the same value, and obviously the mean of samples is a sufficient statistic Is the variance of the sample a sufficient statistic as well? 1) If not, how do I prove ...
yuhao's user avatar
  • 53
1 vote
1 answer
1k views

Poisson sufficient statistics problem

I have the following problem: Let $Y_1, \dots, Y_n$ be a random sample from a Poisson distribution $\text{Pois}(\lambda)$. Recall, the $\text{Pois}(\lambda)$ distribution has the probability function ...
The Pointer's user avatar
  • 2,096
1 vote
2 answers
199 views

Finding the form $g(T(\mathbf{y}), \lambda) \times h(\mathbf{y})$ for sufficiency statistic examples

I'm studying some notes that present examples of sufficiency: Let $Y_1, \dots, Y_n$ be i.i.d. $N(\mu, \sigma^2)$. Note that $\sum_{i = 1}^n (y_i - \mu)^2 = \sum_{i = 1}^n (y_i - \bar{y})^2 + n(\bar{y}...
The Pointer's user avatar
  • 2,096
1 vote
2 answers
8k views

Sufficient statistic for Poisson in wiki?

In Wikipedia: https://en.wikipedia.org/wiki/Sufficient_statistic#Poisson_distribution it says that $X_1+\cdots+X_n$ is a sufficient statistic for the parameter of the Poisson distribution and its ...
Poison's user avatar
  • 19
0 votes
0 answers
2k views

Explain sufficient statistic for Poisson distribution [duplicate]

The Wikipedia entry on this topic is, to me, very confusing. It states that: If X1, ...., Xn are independent and have a Poisson distribution with parameter λ, then the sum T(X) = X1 + ... + Xn is a ...
Gabriel's user avatar
  • 4,352
1 vote
1 answer
85 views

Sufficient statistic vector of single parameter?

Can the sufficient statistic for a single parameter be a vector? In my case, I am finding the sufficient statistics for the Poisson parameter in a HMM mixture. The parameter enters my log likelihood ...
andrew's user avatar
  • 163
1 vote
2 answers
2k views

Sufficiency of two Poisson disributions

If $X_1,X_2$ constitute a random sample of size n=2 from a Poisson Population show that the mean of the sample is a sufficient estimator of the parameter $\lambda$ . Since the sum of Poissons is ...
clarkson's user avatar
  • 1,253
4 votes
0 answers
166 views

Sufficient statistics of posterior (with Poisson data)

Suppose that, for year $t$, the data $y$ is Poisson with mean $a + bt$. Assume also a uniform prior on $(a,b)$. If we have $n$ years of data then I think the posterior for $(a,b)$ will be \begin{...
tony2785's user avatar