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4 votes
1 answer
372 views

Exponential bound for tail of standard normal distributed random variable

Let $X\sim N(0,1)$ and $a\geq 0$. I have to show that $$\mathbb{P}(X\geq a)\leq\frac{\exp(\frac{-a^2}{2})}{1+a}$$ I have no problem showing that $\mathbb{P}(X\geq a)\leq \frac{\exp(\frac{-a^2}{2})}{a\...
stats19's user avatar
  • 103
2 votes
0 answers
92 views

Probabilistic bound on difference of Lipschitz random function

I am currently facing the following problem : Let $(X_1,Z_1),\ldots,(X_n,Z_n)$ be $n$ i.i.d. sample points from some distribution $p$ supported on $\mathcal X\times\{-1,1\}$ where $\mathcal X\subseteq ...
Stratos supports the strike's user avatar
0 votes
3 answers
230 views

Lower bound for $\sqrt{x} - \sqrt{x-1} $ [closed]

Does anyone know any useful lower bound for $\sqrt{x} - \sqrt{x-1} $ for $x>1$. I have a problem where I want to find a lower bound for $$\sqrt{C \log(n)} - \sqrt{C \log(n)-1} $$ for a positive ...
Victor's user avatar
  • 3
1 vote
0 answers
48 views

Upper Bound for Moments for Product of Sample Means

I have a question about the upper bound of the following moment. Suppose that $(A_1, e_1),\ldots, (A_n, e_n)$ are i.i.d. with $E(e_i)=0$. I am wondering if we have the bound $$E\bigg(\bigg\|\frac{\...
beginner's user avatar
1 vote
0 answers
52 views

Does logistic regression not fulfill an inequality required for Wilks' Theorem or am I missing something?

The required inequality: Wilks' Theorem is given in the source below as Theorem 12.4.2, p. 515. Before stating the inequality, some definitions are needed: Let $Z_1, \dots, Z_n$ be i.i.d. according to ...
MathStudent's user avatar
2 votes
0 answers
212 views

Hoeffding's Inequality Assumptions

I'm looking for the assumptions of the Hoeffding's inequality to check it is applicable to my problem. So far the only assumptions I can find are the variables $Z_i$ are IID and bounded. However, Im ...
curiouscat22's user avatar
0 votes
1 answer
110 views

Markov Inequality question confusion bound problem

"If a fair die is rolled 200 times, count the number of 1’s. Give an upper bound for the probability that the count of 1’s stays below 8. " So here for Markov inequality, P(X>=8)<=E[X]/8. So here,...
T2020's user avatar
  • 1
-1 votes
1 answer
3k views

How to find upper bound of a probability?

We roll a fair die 50 times and count the number of 2’s. Give an upper bound for the probability that the count of 2’s stays below 7. How can I approach this problem?
T2020's user avatar
  • 1
1 vote
0 answers
41 views

Nice bounds for 3rd folded central moment in terms of variance?

Say we have some real numbers $x_1, \ldots, x_n$, and let $\mu$ be their mean and $\sigma^2$ be the variance. Are there some nice bounds for $\frac 1n \sum_{i=1}^n |x_i - \mu|^3$ based on $\sigma^2$? ...
D.R.'s user avatar
  • 8,945
3 votes
1 answer
885 views

Lower bounds on sum of squared sub-gaussians

Letting $\left\{X_{i}\right\}_{i=1}^{n}$ be an i.i.d. sequence of zero-mean sub-Gaussian variables with parameter $\sigma,$ define $Z_{n} :=\frac{1}{n} \sum_{i=1}^{n} X_{i}^{2} .$ Prove that $$ \...
david's user avatar
  • 73
1 vote
1 answer
118 views

Inequality involving log-sum-exp, variance, and mean

Fix $z_1,\ldots,z_n \in \mathbb R$. Let $\mu_n:= mean(z_1,\ldots,z_n):=\frac{1}{n}\sum_{i=1}^n z_i$, $lse_n(z_1,\ldots,z_n)=\log(\sum_{i=1}^n e^{z_i})$, and $\sigma^2_n := variance(z_1,\ldots,z_n):=\...
dohmatob's user avatar
  • 9,575