### 统计代写|经济统计代写Economic Statistics代考|ECON227

statistics-lab™ 为您的留学生涯保驾护航 在代写经济统计Economic Statistics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。我们的专家在代写经济统计Economic Statistics代写方面经验极为丰富，各种代写经济统计Economic Statistics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|经济统计代写Economic Statistics代考|Existing Architecture

Table $1.1$ summarizes the source data and statistics produced to measure real and nominal consumer spending. ${ }^3 \mathrm{~A}$ notable feature of the current architecture is that data collection for total retail sales (Census) and for prices (BLS) are completely independent. The consumer price index program collects prices based on (1) expenditure shares from the Consumer Expenditure Survey (BLS manages the survey and Census collects the data), (2) outlets selected based on the Telephone Point of Purchase Survey, and (3) a relatively small sample of goods at these outlets that are chosen probabilistically (via the Commodities and Services Survey). The Census Bureau collects sales data from retailers in its monthly and annual surveys. The monthly survey is voluntary and has suffered from declining response rates. In addition, the composition of the companies responding to the monthly survey can change over time, which complicates producing a consistent time series. Store-level sales data are only collected once every five years as part of the Economic Census.

Integration of nominal sales and prices by BEA is done at a high level of aggregation that is complicated by the availability of product class detail for nominal sales that is only available every five years from the Economic Census. In the intervening periods, BEA interpolates and extrapolates based on the higher frequency annual, quarterly, and monthly surveys of nominal sales by the Census Bureau. These higher frequency surveys are typically at the firm rather than establishment level. Moreover, they classify firms by major kinds of business. For example, sales from the Census Monthly Retail Trade Survey (MRTS) reflect sales from “Grocery Stores” or “Food and Beverage Stores.” Such stores (really firms) sell many items beyond food and beverages, complicating the integration of the price indexes that are available at a finer product-class detail.

This complex decentralized system implies that there is limited granularity in terms of industry or geography in key indicators such as real GDP. BEA’s GDP by industry provides series for about 100 industries, with some 4-digit (NAICS) detail in sectors like manufacturing, but more commonly 3-digit and 2-digit NAICS detail. The BEA recently released county-level GDP on a special release basis, a major accomplishment. However, this achievement required BEA to integrate disparate databases at a high level of aggregation with substantial interpolation and extrapolation. Digitized transactions data offer an alternative, building up from micro data in an internally consistent manner.

## 统计代写|经济统计代写Economic Statistics代考|Using Item- Level Transactions Data

In the results presented here, we focus on two sources of transactions data summarized to the item level. One source is Nielsen retail scanner data, which provide item-level data on expenditures and quantities at the UPC code level for over 35,000 stores, covering mostly grocery stores and some mass merchandisers. ${ }^4$ Any change in product attributes yields a new UPC code so there are no changes in product attributes within the item-level data we use. The Nielsen data cover millions of products in more than 100 detailed product groups (e.g., carbonated beverages) and more than 1,000 modules within these product groups (e.g., soft drinks is a module in carbonated beverages). While the Nielsen scanner item-level data are available weekly at the store level, our analysis aggregates the item-level data to the quarterly, national level.5 Since the weeks may split between months, we use to monthly data. The NRF calendar places complete weeks into months and controls for changes in the timing of holidays and the number of weekends per month, and we use the months to create the quarterly data used in this paper. For more than 650,000 products in a typical quarter, we measure nominal sales, total quantities, and unit prices at the item level. We use the Nielsen scanner data from 2006:1 to 2015:4. The NPD Group (NPD) ${ }^6$ data cover more than 65,000 general merchandise stores, including online retailers, and include products that are not included in the Nielson scanner data. We currently restrict ourselves to the analysis of one detailed product module: memory cards. ${ }^7$ The NPD raw data are at the item-by-store-bymonth level; NPD produces the monthly data by aggregating weekly data using the NRF calendar, as we do ourselves with the Nielsen data. Again, for our analysis we aggregate the data to the quarterly, national item level. For example, the item-level data for memory cards tracks more than 12,000 item-by-quarter observations for the 2014:1 to $2016: 4$ sample period. As with the Nielsen data, we measure nominal sales, total quantities, and unit prices at the item-level by quarter.

## 统计代写|经济统计代写Economic Statistics代考|Existing Architecture

BEA 对名义销售额和价格的整合是在高水平的聚合中完成的，由于名义销售额的产品类别详细信息的可用性而复杂化，而名义销售额的产品类别详细信息仅在经济普查中每五年提供一次。在中间期间，BEA 根据人口普查局对名义销售额的较高频率的年度、季度和月度调查进行内插和外推。这些较高频率的调查通常是在公司而不是机构层面进行的。此外，他们按主要业务类型对公司进行分类。例如，人口普查每月零售贸易调查 (MRTS) 的销售额反映了“杂货店”或“食品和饮料店”的销售额。此类商店（实际上是公司）销售食品和饮料以外的许多商品，从而使价格指数的整合变得复杂，这些价格指数可以在更精细的产品级细节中获得。

## 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。