统计代写|线性回归分析代写linear regression analysis代考|What does an insignificant estimate tell you

如果你也在 怎样代写线性回归分析linear regression analysis这个学科遇到相关的难题,请随时右上角联系我们的24/7代写客服。

回归分析是一种强大的统计方法,允许你检查两个或多个感兴趣的变量之间的关系。虽然有许多类型的回归分析,但它们的核心都是考察一个或多个自变量对因变量的影响。

statistics-lab™ 为您的留学生涯保驾护航 在代写线性回归分析linear regression analysis方面已经树立了自己的口碑, 保证靠谱, 高质且原创的统计Statistics代写服务。我们的专家在代写线性回归分析linear regression analysis代写方面经验极为丰富,各种代写线性回归分析linear regression analysis相关的作业也就用不着说。

我们提供的线性回归分析linear regression analysis及其相关学科的代写,服务范围广, 其中包括但不限于:

  • Statistical Inference 统计推断
  • Statistical Computing 统计计算
  • Advanced Probability Theory 高等楖率论
  • Advanced Mathematical Statistics 高等数理统计学
  • (Generalized) Linear Models 广义线性模型
  • Statistical Machine Learning 统计机器学习
  • Longitudinal Data Analysis 纵向数据分析
  • Foundations of Data Science 数据科学基础

统计代写|线性回归分析代写linear regression analysis代考|What does an insignificant estimate tell you

The basic reason why the lack of evidence is not proof of non-existence is that there are alternative reasons for the lack of evidence. As mentioned earlier, when a jury in a criminal trial deliberates on whether a defendant is guilty, the jury members are not directed to conclude that the defendant has been proven innocent. Rather, they are supposed to determine whether there is significant evidence (beyond a reasonable doubt) that indicates the defendant was guilty. Thus, one reason why a defendant may be found “not guilty” is that there was not enough evidence.

The same concept is supposed to be used for statistical analysis. We are often testing whether a coefficient estimate is different from zero. Let’s say we are examining how class-size affects elementary-school students’ test scores, and let’s say that we find an insignificant estimate on the variable for class-size. In a study of mine (Arkes 2016), I list four general possible explanations for an insignificant estimate:

  1. There is actually no effect of the explanatory variable on the outcome in the population.
  2. There is an effect in one direction, but the model is unable to detect the effect due to a modeling problem (e.g., omitted-factors bias or measurement error – see Chapter 6) biasing the coefficient estimate in a direction opposite to the actual effect.
  1. There is a small effect that cannot be detected with the available data due to inadequate power i.e., not a large enough sample given the size of the effect.
  2. There are varying effects in the population (or sample); some people’s outcomes may be affected positively by the treatment, others’ outcomes may be affected negatively, and others’ outcomes may not be affected; and the estimated effect (which is the average effect) is insignificantly different from zero due to the positive and negative effects canceling each other out or being drowned out by those with zero effects.

So what can you conclude from the insignificant estimate on the class-size variable? You cannot conclude that class size does not affect test scores. Rather, as with the hot hand and the search for aliens, the interpretation should be: “There is no evidence that class-size affects test scores.”

Unfortunately, a very common mistake made in the research world is that the conclusion would be that there is no effect. This is important for issues such as whether there are side effects from pharmaceutical drugs or vaccines. The lack of evidence for a side effect does not mean that there is no effect, particularly if confidence intervals for the estimates include values that would represent meaningful side effects of the drug or vaccine.

All that said, there are sometimes cases in which an insignificant estimate has a $95 \%$ or $99 \%$ confidence interval with a fairly narrow range and outer boundary that, if the boundary were the true population parameter, it would be “practically insignificant” (see Section 5.3.9). If this were the case and the coefficient estimate were not subject to any meaningful bias, then it would be safe to conclude that “there is no meaningful effect.”

统计代写|线性回归分析代写linear regression analysis代考|Statistical significance is not the goal

As we conduct research, our ultimate goal should be to advance knowledge. Our goal should not be to find a statistically-significant estimate. Advancing knowledge occurs by conducting objective and honest research.

A statistically insignificant coefficient estimate on a key-explanatory variable is just as valid as a significant coefficient estimate. The problem, many believe, is that an insignificant estimate may not provide as much information as a significant estimate. As described in the previous section, an insignificant estimate does not necessarily mean that there is no meaningful relationship, and so it could have multiple possible interpretations. If the appropriate confidence intervals for the coefficient were narrow (which would indicate adequate power), the methods were convincing for ruling out modeling problems, and the effects would likely go in just one direction, then it would be more reasonable to conclude that an insignificant estimate indicates there is no meaningful effect of the treatment. But meeting all those conditions is rare, and so there are multiple possible conclusions that cannot be distinguished.

As mentioned in the previous section, a statistically-significant estimate could also be subject to the various interpretations of insignificant estimates. But these are often ignored and not deemed as important, to most people, as long as there is statistical significance.

Statistical significance is valued more, perhaps, because it is evidence confirming, to some extent, the researcher’s theory and/or hypothesis. I conducted a quick, informal review of recent issues of leading economic, financial, and education journals. As it has been historically, almost all empirical studies had statistically-significant coefficient estimates on the key-explanatory variable. Indeed, I had a difficult time finding an insignificant estimate. This suggests that the pattern continues that journals are more likely to publish studies with significant estimates on the key-explanatory variables.

The result of statistical significance being valued more is that it incentivizes researchers to make statistical significance the goal of research. This can lead to $\mathbf{p}$-hacking, which involves changing the set of control variables, the method (e.g. Ordinary Least Squares (OLS) vs. an alternative method, such as in Chapters 8 and 9), the sample requirements, or how the variables (including the outcome) are defined until one achieves a p-value below a major threshold. (I describe p-hacking in more detail in Section 13.3.)

It is unfortunate that insignificant estimates are not accepted more. But, hopefully, this book will be another stepping stone for the movement to be more accepting of insignificant estimates. I personally trust insignificant estimates more than significant estimates (except for the hot hand in basketball).

The bottom line is that, as we conduct research, we should be guided by proper modeling strategies and not by what the results are saying.

线性回归代写

统计代写|线性回归分析代写linear regression analysis代考|What does an insignificant estimate tell you

缺乏证据不能证明不存在的基本原因是缺乏证据还有其他原因。如前所述,当陪审团在刑事审判中审议被告是否有罪时,陪审团成员并没有被指示得出被告已被证明无罪的结论。相反,他们应该确定是否有重要证据(排除合理怀疑)表明被告有罪。因此,被告人可能被判“无罪”的原因之一是证据不足。

同样的概念应该用于统计分析。我们经常测试系数估计值是否不同于零。假设我们正在研究班级规模如何影响小学生的考试成绩,假设我们发现班级规模变量的估计值不显着。在我的一项研究中(Arkes 2016),我列出了对微不足道的估计的四种一般可能解释:

  1. 实际上,解释变量对总体结果没有影响。
  2. 在一个方向上有影响,但由于建模问题(例如,遗漏因素偏差或测量误差——参见第 6 章),模型无法检测到影响系数估计值在与实际影响相反的方向上的偏差。
  1. 由于功效不足,即没有足够大的样本给定效应大小,因此无法用可用数据检测到一个小效应。
  2. 总体(或样本)有不同的影响;某些人的结果可能会受到治疗的积极影响,其他人的结果可能会受到负面影响,而其他人的结果可能不会受到影响;由于正负效应相互抵消或被零效应淹没,因此估计效应(即平均效应)与零无显着差异。

那么,从对班级规模变量的微不足道的估计中,你能得出什么结论呢?您不能断定班级规模不会影响考试成绩。相反,就像热手和寻找外星人一样,解释应该是:“没有证据表明班级规模会影响考试成绩。”

不幸的是,研究界常犯的一个错误是得出的结论是没有效果。这对于诸如药物或疫苗是否有副作用等问题很重要。缺乏副作用的证据并不意味着没有影响,特别是如果估计的置信区间包括代表药物或疫苗有意义的副作用的值。

综上所述,有时在某些情况下,微不足道的估计会产生95%或者99%具有相当窄的范围和外部边界的置信区间,如果边界是真实的人口参数,它将“实际上微不足道”(见第 5.3.9 节)。如果情况确实如此,并且系数估计不受任何有意义的偏差影响,那么可以安全地得出“没有有意义的影响”的结论。

统计代写|线性回归分析代写linear regression analysis代考|Statistical significance is not the goal

当我们进行研究时,我们的最终目标应该是增进知识。我们的目标不应该是找到具有统计意义的估计值。通过进行客观和诚实的研究来提高知识。

对关键解释变量的统计上不显着的系数估计与显着的系数估计一样有效。许多人认为,问题在于微不足道的估计可能无法提供与重要估计一样多的信息。如前一节所述,一个无关紧要的估计并不一定意味着没有有意义的关系,因此它可能有多种可能的解释。如果系数的适当置信区间较窄(这表明有足够的功效),这些方法对于排除建模问题是有说服力的,并且效果可能只朝一个方向发展,那么得出不显着的结论会更合理估计表明治疗没有有意义的效果。但满足所有这些条件是罕见的,

如前一节所述,具有统计意义的估计也可能受到对不重要估计的各种解释的影响。但对大多数人来说,只要具有统计显着性,这些往往会被忽略并且不被视为重要。

统计显着性更受重视,也许是因为它是在某种程度上证实研究人员的理论和/或假设的证据。我对最近几期领先的经济、金融和教育期刊进行了快速、非正式的审查。从历史上看,几乎所有的实证研究都对关键解释变量进行了统计显着的系数估计。事实上,我很难找到一个微不足道的估计。这表明该模式继续存在,即期刊更有可能发表对关键解释变量进行重大估计的研究。

统计显着性被更加重视的结果是它激励研究者将统计显着性作为研究的目标。这会导致p-hacking,涉及更改控制变量集、方法(例如普通最小二乘法 (OLS) 与替代方法,例如第 8 章和第 9 章中的方法)、样本要求或变量(包括结果)的变化方式被定义,直到一个人达到低于主要阈值的 p 值。(我在第 13.3 节中更详细地描述了 p-hacking。)

不幸的是,微不足道的估计不被更多人接受。但是,希望这本书将成为该运动更多地接受微不足道的估计的另一个垫脚石。我个人更相信无关紧要的估计而不是重要的估计(除了篮球中的热手)。

底线是,在我们进行研究时,我们应该以适当的建模策略为指导,而不是以结果的说法为指导。

统计代写|线性回归分析代写linear regression analysis代考 请认准statistics-lab™

统计代写请认准statistics-lab™. statistics-lab™为您的留学生涯保驾护航。

随机过程代考

在概率论概念中,随机过程随机变量的集合。 若一随机系统的样本点是随机函数,则称此函数为样本函数,这一随机系统全部样本函数的集合是一个随机过程。 实际应用中,样本函数的一般定义在时间域或者空间域。 随机过程的实例如股票和汇率的波动、语音信号、视频信号、体温的变化,随机运动如布朗运动、随机徘徊等等。

贝叶斯方法代考

贝叶斯统计概念及数据分析表示使用概率陈述回答有关未知参数的研究问题以及统计范式。后验分布包括关于参数的先验分布,和基于观测数据提供关于参数的信息似然模型。根据选择的先验分布和似然模型,后验分布可以解析或近似,例如,马尔科夫链蒙特卡罗 (MCMC) 方法之一。贝叶斯统计概念及数据分析使用后验分布来形成模型参数的各种摘要,包括点估计,如后验平均值、中位数、百分位数和称为可信区间的区间估计。此外,所有关于模型参数的统计检验都可以表示为基于估计后验分布的概率报表。

广义线性模型代考

广义线性模型(GLM)归属统计学领域,是一种应用灵活的线性回归模型。该模型允许因变量的偏差分布有除了正态分布之外的其它分布。

statistics-lab作为专业的留学生服务机构,多年来已为美国、英国、加拿大、澳洲等留学热门地的学生提供专业的学术服务,包括但不限于Essay代写,Assignment代写,Dissertation代写,Report代写,小组作业代写,Proposal代写,Paper代写,Presentation代写,计算机作业代写,论文修改和润色,网课代做,exam代考等等。写作范围涵盖高中,本科,研究生等海外留学全阶段,辐射金融,经济学,会计学,审计学,管理学等全球99%专业科目。写作团队既有专业英语母语作者,也有海外名校硕博留学生,每位写作老师都拥有过硬的语言能力,专业的学科背景和学术写作经验。我们承诺100%原创,100%专业,100%准时,100%满意。

机器学习代写

随着AI的大潮到来,Machine Learning逐渐成为一个新的学习热点。同时与传统CS相比,Machine Learning在其他领域也有着广泛的应用,因此这门学科成为不仅折磨CS专业同学的“小恶魔”,也是折磨生物、化学、统计等其他学科留学生的“大魔王”。学习Machine learning的一大绊脚石在于使用语言众多,跨学科范围广,所以学习起来尤其困难。但是不管你在学习Machine Learning时遇到任何难题,StudyGate专业导师团队都能为你轻松解决。

多元统计分析代考


基础数据: $N$ 个样本, $P$ 个变量数的单样本,组成的横列的数据表
变量定性: 分类和顺序;变量定量:数值
数学公式的角度分为: 因变量与自变量

时间序列分析代写

随机过程,是依赖于参数的一组随机变量的全体,参数通常是时间。 随机变量是随机现象的数量表现,其时间序列是一组按照时间发生先后顺序进行排列的数据点序列。通常一组时间序列的时间间隔为一恒定值(如1秒,5分钟,12小时,7天,1年),因此时间序列可以作为离散时间数据进行分析处理。研究时间序列数据的意义在于现实中,往往需要研究某个事物其随时间发展变化的规律。这就需要通过研究该事物过去发展的历史记录,以得到其自身发展的规律。

回归分析代写

多元回归分析渐进(Multiple Regression Analysis Asymptotics)属于计量经济学领域,主要是一种数学上的统计分析方法,可以分析复杂情况下各影响因素的数学关系,在自然科学、社会和经济学等多个领域内应用广泛。

MATLAB代写

MATLAB 是一种用于技术计算的高性能语言。它将计算、可视化和编程集成在一个易于使用的环境中,其中问题和解决方案以熟悉的数学符号表示。典型用途包括:数学和计算算法开发建模、仿真和原型制作数据分析、探索和可视化科学和工程图形应用程序开发,包括图形用户界面构建MATLAB 是一个交互式系统,其基本数据元素是一个不需要维度的数组。这使您可以解决许多技术计算问题,尤其是那些具有矩阵和向量公式的问题,而只需用 C 或 Fortran 等标量非交互式语言编写程序所需的时间的一小部分。MATLAB 名称代表矩阵实验室。MATLAB 最初的编写目的是提供对由 LINPACK 和 EISPACK 项目开发的矩阵软件的轻松访问,这两个项目共同代表了矩阵计算软件的最新技术。MATLAB 经过多年的发展,得到了许多用户的投入。在大学环境中,它是数学、工程和科学入门和高级课程的标准教学工具。在工业领域,MATLAB 是高效研究、开发和分析的首选工具。MATLAB 具有一系列称为工具箱的特定于应用程序的解决方案。对于大多数 MATLAB 用户来说非常重要,工具箱允许您学习应用专业技术。工具箱是 MATLAB 函数(M 文件)的综合集合,可扩展 MATLAB 环境以解决特定类别的问题。可用工具箱的领域包括信号处理、控制系统、神经网络、模糊逻辑、小波、仿真等。

R语言代写问卷设计与分析代写
PYTHON代写回归分析与线性模型代写
MATLAB代写方差分析与试验设计代写
STATA代写机器学习/统计学习代写
SPSS代写计量经济学代写
EVIEWS代写时间序列分析代写
EXCEL代写深度学习代写
SQL代写各种数据建模与可视化代写

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