共查询到20条相似文献,搜索用时 31 毫秒
1.
On Conservative Confidence Intervals 总被引:2,自引:0,他引:2
The subject of the paper – (conservative) confidence intervals – originates in applications to auditing. Auditors are interested in upper confidence bounds for an unknown mean for all sample sizes n. The samples are drawn from populations such that often only a few observations are nonzero. The conditional distribution of an observation given that it is nonzero usually has a very irregular shape. However, it can be assumed that observations are bounded. We propose a way to reduce the problem to inequalities for tail probabilities of certain relevant statistics. Note that a traditional approach involving limit theorems forces to impose additional conditions on regularity of samples and leads to approximate or asymptotic bounds. In the case of , as a statistic we can use sample mean, say
, and we have to use Hoeffding [7] inequalities, since currently they are the best available. This leads to upper confidence bounds for which are of (asymptotic) size at most
in the case of risk =0.05, where is the unknown standard deviation. We have
, where
is the bound in a model with normally distributed observations. It seems that the bound is very robust and can be improved replacing Hoeffding's inequalities by more refined ones. The commonly used Stringer bound (it is still not known whether it is an upper confidence bound) is of asymptotic size
c with equality only for Bernoulli distributions, and the ratio c / can be arbitrary large already for rather simple distributions. Our bounds can involve a priori information (professional judgment of an auditor) of type
0 or/and
0, which leads to improvements. Most of the results also hold for sampling without replacement from finite populations. The i.i.d. condition can be replaced by a martingale-type dependence assumption. Finally, the results can be extended to the noni.i.d. case and for settings with several samples. 相似文献
2.
Peter Hellekalek 《Monatshefte für Mathematik》1980,90(4):291-295
Ifp2 is an integer, then every nonnegative integerk is represented by an expression of the form
with integersa
i
(k), 0a
i
(k)p–1,i=0.1,...,s. The radical-inverse function to the basep,
p
(k), is defined by
. The sequence
is uniformly distributed modulo 1 (it may be called a one-dimensional Halton sequence). In the casep=2 it is the van der Corput sequence. The set of all numbers (0, 1] such that the local discrepancy
is bounded inn is determined. 相似文献
3.
By combinatorial means the authors show the existence of thin sub-sets of primes, useful for Goldbach decompositions. For example, there is a set
of primes with
, such that all butO(x(ln x)–A) even integersnx can be written as
. 相似文献
4.
In this paper, Ore extensions in the class of Hopf algebras are studied. The classification theorem enables one to describe the Hopf--Ore extensions for the group algebras, for the algebras
and
, and for the quantum ax + b group. 相似文献
5.
E. S. Dubtsov 《Journal of Mathematical Sciences》2001,107(4):4002-4021
Let K be a compact space, let X be a closed subspace of C(K), and let
be a positive measure on K. The triple
is said to be regular if, for any positive function
and for any
, there exists a function
such that
on K and
. The case where K is the unit sphere in
and the subspace X is invariant with respect to the unitary group is investigated. Sufficient spectral conditions and a necessary condition for the regularity of a triple are obtained. Connections with compactness of certain Hankel operators and applications to interpolation problems are presented. Bibliography: 16 titles. 相似文献
6.
Chihiro Suetake 《Geometriae Dedicata》1994,51(2):123-131
Let be a translation plane of orderq
3,q an odd prime power, whose kern GF(q). Letl
be the line at infinity of . LetG be a solvable collineation group of in the linear translation complement, which acts transitively onl
, and letH be a maximal normal cyclic subgroup ofG. Then the restriction
ofH onl
acts semiregularly onl
and
{1, 2, 3, 6}, where
is the restriction ofG onl
(ifq –1(mod 3), then
{1, 2}). Ifq {3, 5} and
{1, 2}, then is determined completely, using a computer. 相似文献
7.
Johannes Schoissengeier 《Monatshefte für Mathematik》1992,114(2):139-147
A proof of the formula
for locally compact fields
andC
1-isomorphisms :UV, whereU andV are open subsets of
, was never published. In this paper we give two short proofs, one of them is a more elementary variant of the other. 相似文献
8.
J. F. B. M. Kraaijevanger 《Numerische Mathematik》1986,48(3):303-322
Summary This paper deals with polynomial approximations ø(x) to the exponential function exp(x) related to numerical procedures for solving initial value problems. Motivated by positivity and contractivity requirements imposed on these numerical procedures we study the smallest negative argument, denoted by –R(ø), at which ø is absolutely monotonic. For given integersp1,m1 we determine the maximum ofR(ø) when ø varies over the class of all polynomials of a degree m with
(forx0). 相似文献
9.
Proper holomorphic mappings between generalized pseudoellipsoids 总被引:3,自引:0,他引:3
Gilberto Dini Angela Selvaggi Primicerio 《Annali di Matematica Pura ed Applicata》1991,158(1):219-229
Summary We characterize the existence of proper holomorphic mappings between pseudoellipsoids of the form
. If f:()() is any such mapping, the existence of a subgroup of Aut (()) such that
is shown equivalent to a condition on the branch locus of f. 相似文献
10.
Wilhelm Forst 《Numerische Mathematik》1978,30(2):137-147
Summary Letx
0<x
1<...<x
n–1<x
0+2 be nodes having multiplicitiesv
0,...,v
n–1, 1v
k
r (0k<n). We approximate the evaluation functional
,x fixed, and the integral respectively by linear functionals of the form
and determine optimal weights
for the Favard classesW
r
C
2. In the even case
of optimal interpolation these weights are unique except forr=1,x(x
k
+x
k–1)/2 mod 2. Moreover we get periodic polynomial splinesw
k, j
(0k<n, 0j<v
k
) of orderr such that
are the optimal weights. Certain optimal quadrature formulas are shown to be of interpolatory type with respect to these splines. For the odd case
of optimal interpolation we merely have obtained a partial solution.
Bojanov hat in [4, 5] ähnliche Resultate wie wir erzielt. Um Wiederholungen zu vermeiden, werden Resultate, deren Beweise man bereits in [4, 5] findet, nur zitiert 相似文献
11.
E. Getzler 《Compositio Mathematica》2002,132(2):121-135
We calculate the Euler characteristics of the local systems S
k
S
2
on the moduli space
2 of curves of genus 2, where
is the rank 4 local system R
1 *
. 相似文献
12.
Ider Tsevendorj 《Journal of Global Optimization》2001,21(1):1-14
A function F:Rn R is called a piecewise convex function if it can be decomposed into
, where f
j:Rn R is convex for all jM={1,2...,m}. We consider
subject to xD. It generalizes the well-known convex maximization problem. We briefly review global optimality conditions for convex maximization problems and carry one of them to the piecewise-convex case. Our conditions are all written in primal space so that we are able to proposea preliminary algorithm to check them. 相似文献
13.
A renormalization group transformation R
1 has a single stable point
in the space of the analytic circle homeomorphisms with a single cubic critical point and with the rotation number
(the golden mean). Let a homeomorphism T be the C
1-conjugate of
. We let
denote the sequence of distribution functions of the time of the kth entrance to the nth renormalization interval for the homeomorphism T. We prove that for any
, the sequence
has a finite limiting distribution function
, which is continuous in
, and singular on the interval [0,1]. We also study the sequence
for k>1. 相似文献
14.
V. M. Tsvetkov 《Journal of Mathematical Sciences》1999,95(2):2161-2163
It is proved that the rational number field has one, and only one, normal 2-extension (2, t8)/with group isomorphic to
.If is the maximal subfield of a real-closed field, which does not contain
,then the algebraic closure
of is isomorphic to the field
.Bibliography: 7titles.Translated fromZapiski Nauchnykh Seminarov POMI, Vol. 236, 1997, pp. 192–196. 相似文献
15.
Consider a double array
of i.i.d. random variables with mean and variance
and set
. Let
denote the empirical distribution function of Z1, n
,..., Z
N, n
and let be the standard normal distribution function. The main result establishes a functional law of the iterated logarithm for
, where n=n(N) as N. For the proof, some lemmas are derived which may be of independent interest. Some corollaries of the main result are also presented. 相似文献
16.
Pavel Valtr 《Discrete and Computational Geometry》1992,7(1):135-152
For a finite setA of points in the plane, letq(A) denote the ratio of the maximum distance of any pair of points ofA to the minimum distance of any pair of points ofA. Fork>0 letc
(k) denote the largest integerc such that any setA ofk points in general position in the plane, satisfying
for fixed
, contains at leastc convex independent points. We determine the exact asymptotic behavior ofc
(k), proving that there are two positive constants=(), such thatk
1/3c
(k)k
1/3. To establish the upper bound ofc
(k) we construct a set, which also solves (affirmatively) the problem of Alonet al. [1] about the existence of a setA ofk points in general position without a 7-hole (i.e., vertices of a convex 7-gon containing no other points fromA), satisfying
. The construction uses Horton sets, which generalize sets without 7-holes constructed by Horton and which have some interesting properties. 相似文献
17.
E. G. Emel'yanov 《Journal of Mathematical Sciences》1987,38(4):2081-2090
Let A={a1,...,an} and B={b1,...,bm} be systems of distinct points in
, let be a family of homotopic classes Hi,i=1,..., j+m, of closed Jordan curves on, where the classes Hj+l, l=1,...,m, consist of curves that are homotopic to a point curve in b. Let =1,..., j+m be a system of positive numbers and letU be the modulus of the extremal-metric problem for the family and the system . In this paper we investigate the dependence of the modulusU=U(,A,B) on the parameters i and on the disposition of the points ak and b. One shows thatU is a smooth function of the indicated arguments and one obtains expressions for the derivatives
U,
U, and
U. One gives some applications of these results.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 144, pp. 72–82, 1985. 相似文献
18.
David Fried 《Inventiones Mathematicae》1988,91(1):31-51
Summary LetX be a compact complex manifold covered by complex hyperbolicn-space with the induced metric. Each stable horocycle has a cocomplex structure preserved by the geodesic flow. To a closed geodesic one can thus associate a piece of the Poincaré map with a holomorphic fixed point. The resulting Atiyah-Bott fixed point indices, together with the length and multiplicity of as a periodic orbit, determine the contribution of to certain zeta functionsR
p(z), 0pn. From the leading coefficient ofR
p
atZ=0 and the Hodge numbersh
ij
(X) we calculate the Ray-Singer
-torsionT
p
(X). This indicates that the known connections between torsion and the dynamical features of closed orbits continue to hold in the holomorphic category.Corresponding results hold for the
-torsion of a flat unitary bundle, extending certain formulas of Ray and Singer to the casen>1.Partially supported by the Sloan Foundation and the National Science Foundation 相似文献
19.
The C-regularity up to the boundary of solutions to the Dirichlet problem:
is proved, using a comparison principle of L with a Hörmander's type operator X
j
*
Xj, where is a smooth bounded open subset of Rn, and
is a second-order degenerate elliptic operator with smooth coefficients, satisfying the so-called Fefferman-Phong's condition. 相似文献
20.
Given a real sequence {n}n. Suppose that
is a frame for L2[–, ] with bounds A, B. The problem is to find a positive constant L such that for any real sequence {n}n with ¦n –n¦ <L,
is also a frame for L2[–, ]. Balan [1] obtained
arcsin
. This value is a good stability bound of Fourier frames because it covers Kadec's 1/4-theorem
and is better than
(see Duffin and Schaefer [3]). In this paper, a sharper estimate is given. 相似文献