A priori bound for the parameter to be estimated is incorporated into confidence intervals within frequentistic approach in a straightforward and optimal fashion, ensuring the best resolution of non-boundary values as well as robustness for non-physical values of the estimator.
In particle physics, the likelihood ratio ordering principle is frequently used to determine confidence regions. This method has statistical properties that are superior to that of other confidence regions. But it often requires intensive computations involving thousands of toy Monte Carlo datasets. The original paper by Feldman and Cousins contains a recipe to perform the toy MC computation. In this note, we explain their recipe in a more algorithmic way, show its connection to 1-CL plots, and apply it to simple Gaussian situations with boundaries.
The unified approach of Feldman and Cousins allows for exact statistical inference of small signals that commonly arise in high energy physics. It has gained widespread use, for instance, in measurements of neutrino oscillation parameters in long-baseline experiments. However, the approach relies on the Neyman construction of the classical confidence interval and is computationally intensive as it is typically done in a grid-based fashion over the entire parameter space. In this letter, we propose an efficient algorithm for the Feldman-Cousins approach using Gaussian processes to construct con…
When searching for new physics effects, collaborations will often wish to publish upper limits and intervals with a lower confidence level than the threshold they would set to claim an excess or a discovery. However, confidence intervals are typically constructed to provide constant coverage, or probability to contain the true value, with possible overcoverage if the random parameter is discrete. In particular, that means that the confidence interval will contain the $0$-signal case with the same frequency as the confidence level. This paper details a modification to the Feldman-Cousins method…
This paper discusses the amplitude estimation using data originating from a sine-like function as probability density function. If a simple least squares fit is used, a significant bias is observed for small amplitudes. It is shown that a proper treatment using the Feldman-Cousins algorithm of likelihood ratios allows one to construct improved confidence intervals. Using Bayes' theorem a probability density function is derived for the amplitude. It is used in an application to show that it leads to better estimates compared to a simple least squares fit.
Comment on "Including Systematic Uncertainties in Confidence Interval Construction for Poisson Statistics"
Conrad等人最近在一篇论文(Physical Review D 67(2003)012002)中讨论了将系统不确定性纳入置信区间计算的问题。在他们的工作中,探测器效率和背景通量预测的系统不确定性被纳入以下的混合频率-贝叶斯公式的Feldman和Highland,但使用的似然比排序的Feldman和Feldman,以产生“统一”的置信区间。一般来说,所得到的间隔表现得与人们直观预期的一样,即随着不确定性的增加而增加。然而,据指出,对于观测到的事件数量少于预期背景或与预期背景数量相当的情况,间隔有时可能以完全违反直觉的方式表现-在不确定性增加的情况下,最初的间隔会减少,但这仅限于信号效率不确定性增加的情况。在这篇评论中,我们表明,有问题的行为是由于整合的信号效率的不确定性,同时最大限度地提高最佳拟合备择假设的可能性。如果备择假设似然是通过无条件最大化未知信号和信号效率不确定性来确定的,则限值显示正确的直观行为。
The original frequentist approach for computing confidence intervals involves the construction of the confidence belt which provides a mapping of the observation in data into a subset of values for the parameter. There are different prescriptions for constructing the confidence belt, here we use the one provided by Feldman and Cousins. Alternative methods based on the frequentist idea exist, including the delta likelihood method, the $CL_s$ method and a method here referred to as the $p$-value method, which have all been commonly used in high energy experiments. The purpose of this article is …
Suppose an observable x is the measured value (negative or non-negative) of a true mean mu (physically non-negative) in an experiment with a Gaussian resolution function with known fixed rms deviation s. The most powerful one-sided upper confidence limit at 95% C.L. is UL = x+1.64s, which I refer to as the "original diagonal line". Perceived problems in HEP with small or non-physical upper limits for x<0 historically led, for example, to substitution of max(0,x) for x, and eventually to abandonment in the Particle Data Group's Review of Particle Physics of this diagonal line relationship betwe…