### 统计代写|广义线性模型代写generalized linear model代考|BIOS6940

statistics-lab™ 为您的留学生涯保驾护航 在代写广义线性模型generalized linear model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。我们的专家在代写广义线性模型generalized linear model代写方面经验极为丰富，各种代写广义线性模型generalized linear model相关的作业也就用不着说。

• Statistical Inference 统计推断
• Statistical Computing 统计计算
• (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|广义线性模型代写generalized linear model代考|Repeated Measures and Longitudinal Data

In repeated measures designs, there are several individuals and measurements are taken repeatedly on each individual. When these repeated measurements are taken over time, it is called a longitudinal study or, in some applications, a panel study. Typically various covariates concerning the individual are recorded and the interest centers on how the response depends on the covariates over time. Often it is reasonable to believe that the response of each individual has several components: a fixed effect, which is a function of the covariates; a random effect, which expresses the variation between individuals; and an error, which is due to measurement or unrecorded variables.

Suppose each individual has response $y_i$, a vector of length $n_i$ which is modeled conditionally on the random effects $\gamma i$ as:
$$y_i \mid \gamma_i \sim N\left(X_i \boldsymbol{\beta}+Z_i \gamma_i, \sigma^2 \Lambda_i\right)$$
Notice this is very similar to the model used in the previous chapter with the exception of allowing the errors to have a more general covariance ai. As before, we assume that the random effects $\gamma i \sim N\left(0, \sigma^2 D\right)$ so that:
$$y_i \sim N\left(X_i \beta, \Sigma_i\right)$$
where $\Sigma_i=\sigma^2\left(\Lambda_i+Z_i D Z_i^T\right)$.Now suppose we have $M$ individuals and we can assume the errors and random effects between individuals are uncorrelated, then we can combine the data as:
$$y=\left[\begin{array}{l} y_1 \ y_2 \ \cdots \ y_M \end{array}\right] \quad X=\left[\begin{array}{c} X_1 \ X_2 \ \cdots \ X_M \end{array}\right] \quad \gamma=\left[\begin{array}{c} \gamma_1 \ \gamma_2 \ \cdots \ \gamma_M \end{array}\right]$$
and $\tilde{D}=\operatorname{diag}(D, D, \ldots, D), Z=\operatorname{diag}\left(Z_1, \quad Z_2, \ldots, \quad Z_M\right), \quad \Sigma=\operatorname{diag}\left(\Sigma_1, \quad \Sigma_2, \ldots, \quad \Sigma_M\right)$, and $\Lambda=\operatorname{diag}\left(\Lambda_1, \Lambda_2, \ldots, \Lambda_M\right)$. Now we can write the model simply as
$$y \sim N(X \beta, \Sigma) \quad \Sigma=\sigma^2\left(\Lambda+Z \tilde{D} Z^T\right)$$
The log-likelihood for the data is then computed as above and estimation, testing, standard errors and confidence intervals all follow using standard likelihood theory as before. In fact, there is no strong distinction between the methodology used in this and the previous chapter.

## 统计代写|广义线性模型代写generalized linear model代考|Longitudinal Data

The Panel Study of Income Dynamics (PSID), begun in 1968, is a longitudinal study of a representative sample of U.S. individuals described in Hill (1992). The study is conducted at the Survey Research Center, Institute for Social Research, University of Michigan, and is still continuing. There are currently 8700 households in the study and many variables are measured. We chose to analyze a random subset of this data, consisting of 85 heads of household who were aged 25-39 in 1968 and had complete data for at least 11 of the years between 1968 and 1990. The variables included were annual income, gender, years of education and age in 1968:

Now plot the data:
$>$ library (lattice)
$>$ xyplot (income $\sim$ year I person, psid, type=” $1 “$,
subset=(person $<21$ ), strip=FALSE)
The first 20 subjects are shown in Figure 9.1. We see that some individuals have a slowly increasing income, typical of someone in steady employment in the same job. Other individuals have more erratic incomes. We can also show how the incomes vary by sex. Income is more naturally considered on a log-scale:
$$\text { xyplot }(\log (\text { income+100) year I sex, psid, type=” } 1 “)$$

## 有限元方法代写

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## 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。