美国人口普查American census
美国人口普查 Census in America_英语作文
美国人口普查Census in AmericaCensus is very important for every country, it can tell the changes of the population and help the government to carry out some policies. In America, the government counts the population every ten years and the latest census was in 2010. The results of the census show some changes in this country. First, the growth of the population is very slow. It is obvious that the more rich, the less children people want to have, because they want to focus their energy on the career and when they have time, they would rather enjoy the personal hour. Second, the number of immigrants is increasing, which will become the majority of American population. What’s more, the immigrants give birth to children more than the local people do, so it has been predicted that in the future, the gene of blond hair and blue eyes will disappear.人口普查对每个国家都非常重要,它可以显示人口的变化,帮助政府实施一些政策。
一些统计数据的网址
一些统计数据的网址1.美国经济分析局Bearfacts (Bureau of Economic Analysis)/remd/index.htm该站点由美国商业部下属的经济分析局(BEA)建立。
BEA的功能主要是分析和综合大量数据以便创造美国经济的一个连贯模式。
BEA还对国际、国家和地区的经济进行预算和分析。
其中以对国民生产总值(GDP)的预算最为著名。
2.商业统计(美国人口普查局)Business Statistics (US Census Bureau)/epcd/www/sb001.htm该站点上有便于使用的关于公司、就业、薪水和收据的信息。
按照产业类目排列。
3.人口普查局经济信息Census Bureau Economic Information/ftp/pub/econ/www/是美国人口统计局的官方站点。
上面有大量关于美国经济的统计数据。
如美国经济指标;农业、制造业、建筑业、农村和城市的数据;美国商业统计、当前工业报告、经济统计和调查;数据访问工具等等。
4.当前工业报告(美国人口普查局)Current Industrial Reports (US Census Bureau)/pub/cir/www/index.html这里可以看到系列工业报告。
电子数据是唯一的形式,可能要收取一定费用。
5.网上数据(加州大学圣迭戈分校)Data on the Net (UC San Diego )/idata/收集了关于美国经济和其它数据的站点,有注释,可检索。
6.经济数据和链接(美国加州大学Fresno分校)Econ Data & Links (CAL State Fresno)/Economics/econ_EDL.htm由美国加州大学Fresno分校建立。
该站点提供了大量表格和统计数据,以及很多相关站点的链接,内容从收入、财富到贫困问题都有。
7.经济数据(国际)EconData (International)/EdRes/Top.../International/马里兰大学提供的国际性EconData时间序列数据库。
机器学习_US Census Data (1990) Data Set(美国人口普查数据(1990)数据集)
US Census Data (1990) Data Set(美国人口普查数据(1990)数据集)数据摘要:The US Census1990raw data set contains a one percent sample of the Public Use Microdata Samples (PUMS) person records drawn from the full 1990 census sample.中文关键词:多变量,聚类,UCI,人口普查,美国,英文关键词:Multivariate,Clustering,UCI,Census,US,数据格式:TEXT数据用途:This data set is used for clustering数据详细介绍:US Census Data (1990) Data SetAbstract: The USCensus1990raw data set contains a one percent sample of the Public Use Microdata Samples (PUMS) person records drawn from the full 1990 census sample.Source:The USCensus1990raw data set was obtained from the (U.S. Department of Commerce) Census Bureau website using the Data Extraction System. This system can be found at /DES/www/des.html.Donors:Chris Meek, Microsoft, meek '@' Bo Thiesson, Microsoft, thiesson '@' David Heckerman, Microsoft, heckerma '@' Data Set Information:The data was collected as part of the 1990 census.There are 68 categorical attributes. This data set was derived from the USCensus1990raw data set. The attributes are listed in the file USCensus1990.attributes.txt (repeated below) and the coding for the values is described below. Many of the less useful attributes in the original data set have been dropped, the few continuous variables have been discretized and the few discrete variables that have a large number of possible values have been collapsed to have fewer possible values.More specifically the USCensus1990 data set was obtained from the USCensus1990raw data set by the following sequence of operations;- Randomization: The order of the cases in the original USCensus1990raw data set were randomly permuted.- Selection of attributes: The 68 attributes included in the data set are given below. In the USCensus1990 data set we have added a single letter prefix to the original name. We add the letter 'i' to indicate that the original attribute values are used and 'd' to indicate that originalattribute values for each case have been mapped to new values (the precise mapping is described below).Hierarchies of values are provided in the file USCensus1990raw.coding.htm and the mapping functions used to transform the USCensus1990raw to the USCensus1990 data sets are giving in the file USCensus1990.mapping.sql.The data is contained in a file called USCensus1990.data.txt. The first row contains the list of attributes. The first attribute is a caseid and should be ignored during analysis. The data is comma delimited with one case per row.Attribute Information:--------------------------------------------------------------Old Variable New Variable--------------------------------------------------------------Age dAgeAncstry1 dAncstry1Ancstry2 dAncstry2Avail iAvailCitizen iCitizenClass iClassDepart dDepartDisabl1 iDisabl1Disabl2 iDisabl2English iEnglishFeb55 iFeb55Fertil iFertilHispanic dHispanicHour89 dHour89Hours dHoursImmigr iImmigrIncome1 dIncome1Income2 dIncome2Income3 dIncome3Income4 dIncome4Income5 dIncome5Income6 dIncome6Income7 dIncome7Income8 dIncome8Industry dIndustryKorean iKoreanLang1 iLang1Looking iLookingMarital iMaritalMay75880 iMay75880Means iMeansMilitary iMilitaryMobility iMobilityMobillim iMobillimOccup dOccupOthrserv iOthrservPerscare iPerscarePOB dPOBPoverty dPovertyPwgt1 dPwgt1Ragechld iRagechldRearning dRearningRelat1 iRelat1Relat2 iRelat2Remplpar iRemplparRiders iRidersRlabor iRlaborRownchld iRownchldRpincome dRpincomeRPOB iRPOBRrelchld iRrelchldRspouse iRspouseRvetserv iRvetservSchool iSchoolSept80 iSept80Sex iSexSubfam1 iSubfam1Subfam2 iSubfam2Tmpabsnt iTmpabsntTravtime dTravtimeVietnam iVietnamWeek89 dWeek89Work89 iWork89Worklwk iWorklwkWWII iWWIIYearsch iYearschYearwrk iYearwrkYrsserv dYrsservMapping: In this step we map all of the old values for variables with prefix 'd' to new values. The mappings for the variables dAncstry1, dAncstry2, dHispanic, dIndustry, dOccup, dPOBwere designed to correspond to a natural coarsening of the original values based on the information in the file coding.htm. The remaining variables are continuous valued variables and the mapping for these variables was chosen to make variables that were fairly uniformly distributed across the states (quantiles). The precise mappings are specified in the file USCensus1990.mapping.sql. This file contains all of T-SQL procedures used to map the variables. These procedures can be used directly in SQLServer to map the original values or translated to some other language.--------------------------------------------------------------Variable Procedure--------------------------------------------------------------dAge discAgedAncstry1 discAncstry1dAncstry2 discAncstry2dHispanic discHispanicdHour89 discHour89dHours discHoursdIncome1 discIncome1dIncome2 discIncome2to8dIncome3 discIncome2to8dIncome4 discIncome2to8dIncome5 discIncome2to8dIncome6 discIncome2to8dIncome7 discIncome2to8dIncome8 discIncome2to8dIndustry discIndustrydOccup discOccupdPOB discPOBdPoverty discPovertydPwgt1 discPwgt1dRearning discRearningdRpincome discRpincomedTravtime discTravtimedWeek89 discWeek89dYrsserv discYrsservRelevant Papers:Meek, Thiesson, and Heckerman (2001), "The Learning Curve Method Applied to Clustering", to appear in The Journal of Machine Learning Research.[Web Link]数据预览:点此下载完整数据集。
2019年高中英语作文-美国人口普查
高中Байду номын сангаас语美国人口普查
Census is very important for every country, it can tell the changes of the population and help the government to carry out some policies. In America, the government counts the population every ten years and the latest census was in 2010. The results of the census show some changes in this country. First, the growth of the population is very slow. It is obvious that the more rich, the less children people want to have, because they want to focus their energy on the career and when they have time, they would rather enjoy the personal hour. Second, the number of immigrants is increasing, which will become the majority of American population. What’s more, the immigrants give birth to children more than the local people do, so it has been predicted that in the future, the gene of blond hair and blue eyes will disappear.
美国10年人口普查表格中文对照版Chinese-Simplified
w w 由此开始
w w w 1.2.w w w 在所有适用项上标记 请不要计算离家上大学或参军的人。
请不要计算在监狱、看守所、拘留所等机构内的人。
即使这些人将在离开大学、安养中心/养老院、军队或监狱
等机构后返回这里,请都不要将这些人填写在这个表格里。
不然,他们就可能会被统计两次。
在 2010 年 4 人暂住在这里,请包括这个人。
不然,人口普查就可能会把他漏掉。
人口普查还必须包括没有永久居住地的人,因此:
人口普查局还要在其它机构和地方进行人口统计,因此:
请包括大部分时间都在这里居住和睡觉的所有的人,
包括婴儿。
在 2010 年 4 月 1 房屋里居住或暂住?
除了在第一题已经包括的人以外,是否还有其他人在4月 1 日暂住在这里?
这次人口普查必须统计在回答第 1 题以前,请您按以下规定,计算住在这所房子、公寓或移动式房屋里的人数。
请使用蓝色或黑色笔填写。
这份指南提供了 2010请在这份指南中找到您的答案,然后在寄回填写完毕的 2010人口数 =。
美国人口普查资料
2002年美国人口普查局发布的几份报告2002年美国人口普查局发布的几份报告美国人口普查局报告发表:《美国参考》2002年2-6月;学术交流网/网友学术交流/200 2年7月15日发布;学术交流网/美国统计资料/2002年8月19日重发(一)美国人口普查局从全球角度分析美国人口据美国人口普查局2月6日发布的报告,美国人口为2.81亿,仍是仅次于中国和印度的世界人口第三大国。
2002年2月6日人口普查局参照全球状况分析美国情况并确定老龄化和人口出生率的发展趋势根据商务部人口普查局今天发表的一份分析报告,90年代美国人口增加13%,使其继续保持世界人口第三大国的地位。
根据一份题为《从全球范围看美国人口》的2000年人口普查简报,2000年的美国人口超过除中国(13亿)和印度(10亿)以外的世界任何国家。
世界人口总数为61亿。
人口普查局国际项目中心的负责人彼德·韦说:“一个国家的人口总数只能反映其人口状况的一小方面。
一个国家的人口增长率和年龄-性别结构能说明这个国家所面临的挑战,体现在为儿童和老年人提供医疗保健,让青少年受教育,为年轻人提供工作机会和老年福利等方面。
”美国15岁以下的人口占世界15岁以下总人口的3%,在所有国家中居第四位。
美国的老年人口占世界老年人口总数的8%,在所有国家中居第三位。
这份简报指出了美国和其它发达国家年龄结构的变化。
例如,很多发达国家五岁以下的儿童人数在90年代后期都有所下降。
这份报告说,人口出生率低的国家将在未来的几十年中面临老年人口增加,新劳工人数减少。
美国人口目前占世界人口总数的不到5%,但是美国90年代的增长率是所有其它工业化国家增长率总和的五倍:13%对2.5%。
90年代人口大幅度增长的其它世界大国有:印度,增长率为19%;中国,增长率为11%;尼日利亚,增长率为33%;以及印度尼西亚,增长率为19%。
这些国家和美国增加的人口占90年代全球人口增长总数的将近一半。
解读美2010人口普查
解读美2010人口普查环球时报特约记者李雪报道美国《时代》杂志12月21日发表题为《美国2010年人口普查结果透露何种信息》的文章,从对经济、政治等领域可能产生的影响,对美国2010年人口普查结果进行了深入分析。
总人口首破3亿大关三大原因致增速放缓12月21日,美国人口普查局公布的统计结果显示,截至2010年4月1日,美国总人口达到3亿874万5538人,较2000年的2亿8142万1906人增长9.7%。
这意味着美国总人口有史以来首次突破3亿。
不过,过去十年也是1940年以来美国人口增速最低的十年。
上世纪30年代,经济“大萧条”导致美国人口增速放缓。
分析认为,2000年以来美国人口增速下降主要有三大原因:一是两次经济衰退;二是对于移民的警觉性日益增强;三是海外对于美国的观感日渐恶化。
然而,美国新罕布什尔州立大学人口学教授肯尼思•约翰逊指出:“美国人口增长速度依然很快。
但是这一统计结果显示,过去十年的最后一段时间里,移民进入美国的速度显著放缓。
”与上个千年最后十年的人口增长速度相比,过去十年的人口成长速度显著放缓。
当时(1990年至2000年),美国总人口大增13%。
有分析表示,美国人口成长主要来自于国内新生儿。
据约翰逊教授估计,过去十年新增的约2700万美国人中,1700万为美国国内新生儿,另外1000万新增常住人口则由移民构成。
美国人口普查局局长罗伯特•葛罗夫斯也表示,很难确切地说,是否是经济严重衰退和移民管制更加严格造成美国人口成长趋缓。
他也指出,约60%的人口增长是新生儿,移民仅占40%。
人口日渐西南移加州独占鳌头此次普查的对象是美国50个州和哥伦比亚特区的常住人口。
普查结果显示,从地区看,美国人口日渐向南部和西部转移。
数据显示,过去十年,美国南部和西部人口大量增加,分别增加约1432万人和875万人。
东北部和中西部地区人口也有所增加,但增长速度较慢,分别增加约172万人和253万人。
有分析认为,如果不是经济严重衰退毁损诸如拉斯维加斯和菲尼克斯在内的西部大都市的住房市场,西部和南部的人口增长幅度可能更大。
机器学习_US Census Data (1990) Data Set(美国人口普查数据(1990)数据集)
US Census Data (1990) Data Set(美国人口普查数据(1990)数据集)数据摘要:The US Census1990raw data set contains a one percent sample of the Public Use Microdata Samples (PUMS) person records drawn from the full 1990 census sample.中文关键词:多变量,聚类,UCI,人口普查,美国,英文关键词:Multivariate,Clustering,UCI,Census,US,数据格式:TEXT数据用途:This data set is used for clustering数据详细介绍:US Census Data (1990) Data SetAbstract: The USCensus1990raw data set contains a one percent sample of the Public Use Microdata Samples (PUMS) person records drawn from the full 1990 census sample.Source:The USCensus1990raw data set was obtained from the (U.S. Department of Commerce) Census Bureau website using the Data Extraction System. This system can be found at /DES/www/des.html.Donors:Chris Meek, Microsoft, meek '@' Bo Thiesson, Microsoft, thiesson '@' David Heckerman, Microsoft, heckerma '@' Data Set Information:The data was collected as part of the 1990 census.There are 68 categorical attributes. This data set was derived from the USCensus1990raw data set. The attributes are listed in the file USCensus1990.attributes.txt (repeated below) and the coding for the values is described below. Many of the less useful attributes in the original data set have been dropped, the few continuous variables have been discretized and the few discrete variables that have a large number of possible values have been collapsed to have fewer possible values.More specifically the USCensus1990 data set was obtained from the USCensus1990raw data set by the following sequence of operations;- Randomization: The order of the cases in the original USCensus1990raw data set were randomly permuted.- Selection of attributes: The 68 attributes included in the data set are given below. In the USCensus1990 data set we have added a single letter prefix to the original name. We add the letter 'i' to indicate that the original attribute values are used and 'd' to indicate that originalattribute values for each case have been mapped to new values (the precise mapping is described below).Hierarchies of values are provided in the file USCensus1990raw.coding.htm and the mapping functions used to transform the USCensus1990raw to the USCensus1990 data sets are giving in the file USCensus1990.mapping.sql.The data is contained in a file called USCensus1990.data.txt. The first row contains the list of attributes. The first attribute is a caseid and should be ignored during analysis. The data is comma delimited with one case per row.Attribute Information:--------------------------------------------------------------Old Variable New Variable--------------------------------------------------------------Age dAgeAncstry1 dAncstry1Ancstry2 dAncstry2Avail iAvailCitizen iCitizenClass iClassDepart dDepartDisabl1 iDisabl1Disabl2 iDisabl2English iEnglishFeb55 iFeb55Fertil iFertilHispanic dHispanicHour89 dHour89Hours dHoursImmigr iImmigrIncome1 dIncome1Income2 dIncome2Income3 dIncome3Income4 dIncome4Income5 dIncome5Income6 dIncome6Income7 dIncome7Income8 dIncome8Industry dIndustryKorean iKoreanLang1 iLang1Looking iLookingMarital iMaritalMay75880 iMay75880Means iMeansMilitary iMilitaryMobility iMobilityMobillim iMobillimOccup dOccupOthrserv iOthrservPerscare iPerscarePOB dPOBPoverty dPovertyPwgt1 dPwgt1Ragechld iRagechldRearning dRearningRelat1 iRelat1Relat2 iRelat2Remplpar iRemplparRiders iRidersRlabor iRlaborRownchld iRownchldRpincome dRpincomeRPOB iRPOBRrelchld iRrelchldRspouse iRspouseRvetserv iRvetservSchool iSchoolSept80 iSept80Sex iSexSubfam1 iSubfam1Subfam2 iSubfam2Tmpabsnt iTmpabsntTravtime dTravtimeVietnam iVietnamWeek89 dWeek89Work89 iWork89Worklwk iWorklwkWWII iWWIIYearsch iYearschYearwrk iYearwrkYrsserv dYrsservMapping: In this step we map all of the old values for variables with prefix 'd' to new values. The mappings for the variables dAncstry1, dAncstry2, dHispanic, dIndustry, dOccup, dPOBwere designed to correspond to a natural coarsening of the original values based on the information in the file coding.htm. The remaining variables are continuous valued variables and the mapping for these variables was chosen to make variables that were fairly uniformly distributed across the states (quantiles). The precise mappings are specified in the file USCensus1990.mapping.sql. This file contains all of T-SQL procedures used to map the variables. These procedures can be used directly in SQLServer to map the original values or translated to some other language.--------------------------------------------------------------Variable Procedure--------------------------------------------------------------dAge discAgedAncstry1 discAncstry1dAncstry2 discAncstry2dHispanic discHispanicdHour89 discHour89dHours discHoursdIncome1 discIncome1dIncome2 discIncome2to8dIncome3 discIncome2to8dIncome4 discIncome2to8dIncome5 discIncome2to8dIncome6 discIncome2to8dIncome7 discIncome2to8dIncome8 discIncome2to8dIndustry discIndustrydOccup discOccupdPOB discPOBdPoverty discPovertydPwgt1 discPwgt1dRearning discRearningdRpincome discRpincomedTravtime discTravtimedWeek89 discWeek89dYrsserv discYrsservRelevant Papers:Meek, Thiesson, and Heckerman (2001), "The Learning Curve Method Applied to Clustering", to appear in The Journal of Machine Learning Research.[Web Link]数据预览:点此下载完整数据集。
美国贫困线标准2024
美国贫困线标准2024美国贫困线标准2024根据美国国家政府的定义,贫困线是指一个家庭根据其家庭人数和收入水平来确定是否属于贫困人口的标准。
贫困线的制定是为了帮助政府和社会组织了解和解决贫困问题。
1. 根据美国人口普查局(Census Bureau)的定义,2024年贫困线标准的依据是2024年的生活费用指数(Consumer Price Index,CPI)。
根据CPI的测算结果,美国贫困线的定义与家庭人口数量和州际差异相关。
2.单人家庭的贫困线:对于一个成年人而言,其年收入低于12,880美元即被定义为贫困。
这一数字基于饮食、住房、交通、医疗保健、衣物和其他日常开销的消费水平。
3.双人家庭的贫困线:对于一个居住在美国的双人家庭而言,其年收入低于17,420美元即被定义为贫困。
4.三人家庭的贫困线:对于一个居住在美国的三人家庭而言,其年收入低于21,960美元即被定义为贫困。
5.四人家庭的贫困线:对于一个居住在美国的四人家庭而言,其年收入低于26,500美元即被定义为贫困。
6.更大家庭的贫困线:对于超过四个人的家庭,每增加一个人,贫困线将相应增加4,540美元。
需要指出的是,这些贫困线标准只是作为一个基准来使用,并不能全面反映一个家庭是否真正贫困。
实际上,美国的贫困状况相当复杂,还涉及到诸多其他因素,例如地理位置、教育水平、就业机会、健康状况等等。
此外,还值得关注的是,由于COVID-19疫情的冲击,2024年以来,美国的贫困率有可能增加,因为许多人失去了工作、收入下降或者健康开支增加。
因此,贫困线标准也需要根据具体情况进行动态调整,以反映时代的变化和特殊情况的影响。
总的来说,美国贫困线标准提供了一个衡量贫困状况的参考,但实际中仍需要结合其他因素和具体情况来进行综合评估和分析。
政府和社会组织应该进一步努力,通过采取有效的政策和措施,减少贫困并改善贫困人口的生活状况。
美国2010年人口普查统计资料
1)人口:三点一亿,人口数量列全球第三。(Population: 310,232,863 (Ju world: 3)
2)年龄结构:0-14岁:20.1%;15-64岁:66.9%;65岁以上:13% [Age structure: 0-14 years: 20.1% (male 31,853,857/female 30,526,753) 15-64 years: 66.9% (male 103,607,835/female 104,015,706) 65 years and over: 13% (male 17,291,694/female 22,937,018) (2010 est.)]
7)迁徙率:4.25/1,000 [Net migration rate: 4.25 migrant(s)/1,000 population (2010 est.)]
8)性别比例:出生时:1.047男/女;15岁以下:1.04男/女;15-64岁:1男/女;65岁以上:0.75男/女;总人口:0.97男/女 [Sex ratio: at birth: 1.047 male(s)/female under 15 years: 1.04 male(s)/female 15-64 years: 1 male(s)/female 65 years and over: 0.75 male(s)/female total population: 0.97 male(s)/female (2010 est.)]
13)国籍:美利坚 [Nationality: noun: American(s) adjective: American]
14)种族:白人79.96%, 黑人12.85%, 亚洲人4.43%, 美国印第安人和阿拉斯加土著人0.97%, 夏威夷和其他太平洋诸岛土著人0.18%, 其他种族1.61% [Ethnic groups: white 79.96%, black 12.85%, Asian 4.43%, Amerindian and Alaska native 0.97%, native Hawaiian and other Pacific islander 0.18%, two or more races 1.61% (July 2007 estimate) note: a separate listing for Hispanic is not included because the US Census Bureau considers Hispanic to mean persons of Spanish/Hispanic/Latino origin including those of Mexican, Cuban, Puerto Rican, Dominican Republic, Spanish, and Central or South American origin living in the US who may be of any race or ethnic group (white, black, Asian, etc.); about 15.1% of the total US population is Hispanic]
2016考研阅读英语二text3
题目:2016考研阅读英语二text31. 文章概述2016年考研英语二阅读理解部分的text3是一篇关于美国人口普查的文章。
文章主要讨论了美国人口普查的历史、目的以及对社会的影响。
通过对这篇文章的阅读,能够了解美国人口普查的重要性和其对社会的作用。
2. 文章结构本文分为以下几个部分进行分析:- 美国人口普查的历史- 美国人口普查的目的- 美国人口普查对社会的影响- 美国人口普查的未来发展3. 美国人口普查的历史美国人口普查的历史可以追溯到19世纪初。
在文章中,作者详细分析了美国人口普查从最初的目的到如今的发展变化,以及各个时期的调查重点和方法。
通过深入了解美国人口普查的历史,可以更好地理解其在当今社会中的作用和意义。
4. 美国人口普查的目的美国人口普查不仅仅是对人口数量的统计,更重要的是为政府提供有效的政策制定和资源分配依据。
在文章中,作者分析了美国人口普查对政府决策的重要性,以及如何通过人口普查数据来合理规划社会资源和服务。
5. 美国人口普查对社会的影响美国人口普查的数据不仅对政府决策有着重要影响,同时也能够反映社会的变化和趋势。
文章中探讨了人口普查数据对社会发展和经济状况的影响,以及如何通过数据分析来解决社会问题和改善公共服务。
6. 美国人口普查的未来发展随着科技的进步和社会的发展,美国人口普查也在不断更新和发展。
文章中提到了未来人口普查可能面临的挑战和发展方向,以及如何更好地利用新技术和方法来进行人口普查,使其更加准确和全面。
7. 总结通过对这篇文章的阅读,我们深入了解了美国人口普查的历史、目的、对社会的影响以及未来发展方向。
人口普查作为一项重要的社会调查工作,对政府决策和社会发展都有着重要的意义。
希望通过这篇文章的阅读,能够对考研英语阅读理解部分的复习有所帮助。
8. 现代科技对人口普查的影响随着现代科技的不断进步,人口普查所采用的调查方法也在不断更新和改进。
现代科技如大数据、人工智能、地理信息系统等技术的应用,为人口普查提供了更为便捷和高效的手段。
工具变量法(二):弱工具变量
⼯具变量法(⼆):弱⼯具变量世上没有完美的计量⽅法,因为所有的计量⽅法与模型均依赖于⼀定的前提假设。
因此,在估计完计量模型后,通常需要对模型的前提假设进⾏检验,称为 “诊断性检验”(diagnostic checking)或 “模型检验”(model checking)。
⼯具变量法也不例外。
⼯具变量法的成⽴依赖于有效的⼯具变量(valid instruments),即所使⽤的⼯具变量须满⾜相关性(与内⽣解释变量相关)与外⽣性(与扰动项不相关)。
⼯具变量的相关性(Instrument Relevance)在⼤样本下,2SLS为⼀致估计。
但对于⼤多数实践中的有限样本(finite sample),2SLS估计量依然存在偏差(bias),并不以真实参数为其分布的中⼼,即⽽且,如果⼯具变量与内⽣变量的相关性较弱,则 2SLS 的偏差会变得更为严重。
直观来看,2SLS 的基本思想是通过外⽣的⼯具变量,从内⽣变量中分离出⼀部分外⽣变动(exogenous variations),以获得⼀致估计。
如果⼯具变量与内⽣变量的相关性很弱,则通过⼯具变量分离出的内⽣变量之外⽣变动仅包含很少的信息。
因此,利⽤这些少量信息进⾏的⼯具变量法估计就不准确,即使样本容量很⼤也很难收敛到真实的参数值。
这种⼯具变量称为 “弱⼯具变量”(weak instruments)。
弱⼯具变量的后果弱⼯具变量的后果类似于样本容量过⼩,会导致 2SLS 的⼩样本性质变得很差,⽽ 2SLS 的⼤样本分布也可能离正态分布相去甚远,致使基于⼤样本理论的统计推断失效。
下⾯通过蒙特卡洛模拟(Monte Carlo simulation)来直观地考察弱⼯具变量的后果。
考虑最简单的⼀元回归模型,假设其数据⽣成过程(data generating process)为:其中,为内⽣变量,与扰动项相关;⽽的真实系数为 2。
假设样本容量为10,000,并使⽤⼯具变量进⾏ 2SLS 回归。
American Population 美国人口英文简介
U.S. population growth is among the highest in developed countries
an urbanized城市化的 nation with 80.8 percent of its population residing居住于 in cities and suburbs郊外.
In 2006, 254 incorporated合并的 places had populations over 100,000, nine cities had more than 1 million residents, and four global cities had over 2 million (New York City, Los Angeles, Chicago, and Houston).
Questions:
6. How did the black people come to the United States? What was their fate 命运in the U.S.? What role did the Chinese-American 华裔美国人play in the development of the United States? How were they treated? How are the Chinese-Americans doing today? What was the fate of the Indians in the course of the development of the United States?
east west rural areas cities south other areas Northeast/ central north west/south
美国人口普查方法介绍
美国 2010 年人口普查方法介绍陈婉清内容提要:本文介绍了美国 2010 年人口普查的调查目的、内容、具体组织实施方法等,其科学的调查设计方法、规范的操作流程、先进的数据收集和处理方法及丰富的公开信息资源,为我国 2010 年人口普查提供了参考,有利于加快完善我国人口普查制度,及时准确地反映全国及各地的人口变化情况。
关键词:美国;人口普查;方法一、美国 2010 年人口普查介绍( 一 ) 背景资料1. 人口普查历史。
1790年,美国第一次人口普查由特警骑马入户进行访问,所统计的人口总数为390万,之后每隔10年(在尾数为0的年份)进行一次人口普查。
1880年,由专业统计员取代美国特警成为人口普查员。
1940年,美国人口普查局首次对人口普查长表实施统计抽样调查。
1950年,首次使用电子计算机来汇总普查结果。
1960年,随着人口快速增长、多元化及流动性增强,普查表格第一次通过邮寄方式分发到城市地区的家庭(在此之前是以人户访问的形式完成的)。
数据采集自动化进程引入光学标记识别设备。
1990 年,人口普查引人地理信息系统。
美国人口普查局开发电子数据收集方法,包括电脑辅助个人访问和电脑辅助电话访问作为邮寄调查的补充,有助于降低成本。
2000 年,人口普查局雇用 86 万临时工进行普查,雇用一家私人公司进行全国性宣传运动,以扭转自1970 年以来邮件答复率持续下降的趋势。
至2000 年人口普查 , 美国人口总数已超过 2.8 亿。
2. 普查目的和重要性。
人口普查主要目的是统计美国的人口总数 , 还有其他重要用途 : 人口普查数据决定着联邦和州政府如何分摊 3000 亿美元的年度资金 ; 用于分配美国各州议会代表席位 ; 用于分配学校经费、就业服务、公路补助、住房建设、医疗服务、养老计划等方面的联邦资金 ; 银行、保险公司、卫生保健机构以及零售商业企业都需要普查数据 ; 几乎所有的商业机构都需要目标销售地区的消费者信息 ; 让美国的领导者了解到国民概况和需求。
census bureau 意思
census bureau 意思英文回答:The United States Census Bureau is a federal agency responsible for collecting, analyzing, and disseminating statistical data about the population and economy of the United States. The Census Bureau conducts the decennial census, which counts the population of the United States every 10 years, and the American Community Survey, which collects data on social, economic, and housing characteristics of the U.S. population. The Census Bureau also collects data on business and industry, foreign trade, governments, and other topics.The Census Bureau's mission is to provide accurate and timely data to inform decision-making by government officials, businesses, and the public. The data collected by the Census Bureau is used to allocate federal funds, draw congressional and state legislative districts, and inform policy decisions at all levels of government. Thedata is also used by businesses to make decisions about where to locate new facilities and how to market their products and services.The Census Bureau is committed to protecting the confidentiality of the data it collects. The data collected by the Census Bureau is confidential by law, and the Census Bureau takes a number of steps to protect the privacy of respondents. For example, the Census Bureau does not release any data that could be used to identify an individual respondent.The Census Bureau is a vital part of the U.S.statistical system. The data collected by the Census Bureau is used to inform decision-making at all levels of government and by businesses and the public. The Census Bureau is committed to providing accurate and timely data to meet the needs of its users.中文回答:美国人口普查局是一个联邦机构,负责收集、分析和传播有关美国人口和经济的统计数据。
2018年6月大学英语六级真题、译文及详细解析
2018年6月大学英语六级考试仔细阅读真题解析(卷二)Section CDirections:There are 2 passages in this section. Each passage is followed by some questions or unfinished statements. For each of them there are four choices marked A),B),C)and D).You should decide on the best choice and mark the corresponding letter on Answer Sheet 2 with a single line through the centre.Passage OneQuestions 46 to 50 are based on the following passage.Economically speaking, are we better off than we were ten years ago Twenty years agoIn their thirst for evidence on this issue, commentators seized on the recent report by the Census Bureau, which found that average household income rose by % in 2015. Unfortunately, that conclusion puts too much weight on a useful, but flawed and incomplete, statistic. Among the more significant problems with the Census’s measure are that: 1) it excludes taxes, transfers, and compensation like employer-provided health insurance; and 2) it is based on surveys rather than data. Even if precisely measured, income data exclude important determinants of economic well-being, such as the hours of work needed to earn that income.While thinking about the question, we came across a recently published article by Charles Jones and Peter Klenow, which proposes an interesting new measure of economic welfare. While by no means perfect, it is considerably more comprehensive than average income, taking into account not only growth in consumption per person but also changes in working time, life expectancy, and inequality. Moreover, it can be used to assess economic performance both across countries and over time.The Jones-Klenow method can be illustrated by a cross-country example. Suppose we want to compare the economic welfare of citizens of the . and France in 2005.In 2005, as the authors observe, real consumption per person in France was only 60% as high as the ., making it appear that Americans were economically much better off than the French on average. However, that comparison omits other relevant factors: leisure time, life expectancy, and economic inequality. The French take longer vacations and retire earlier, so typically work fewer hours; they enjoy a higher life expectancy, presumably reflecting advantages with respect to health care, diet, lifestyle, and the like; and income and consumption are somewhat more equally distributed there than in the . Because of these differences, comparing France’s consumption with the .’s overstates the gap ineconomic welfare.Similar calculations can be used to compare the . and other countries. For example, this calculation puts economic welfare in the United Kingdom at 97% of . levels, but estimates Mexican well-being at 22%.The Jones-Klenow measure can also assess an economy’s performance over time. According to this measure, as of the early-to-mid-2000s, the . had the highest economic welfare of any large country. Since 2007, economic welfare in the . has continued to improve. However, the pace of improvement has slowed markedly.Methodologically, the lesson from the Jones-Klenow research is that economic welfare is multi-dimensional. Their approach is flexible enough that in principle other important quality-of life changes could be incorporated—for example, decreases in total emissions of pollutants and declines in crime rates.全文翻译及命题分析从经济上讲,我们的生活比十年前或二十年前更好吗评论员从美国人口普查局最新的一份报告着手,渴望在这个问题上找到证据。
acs标准
ACS标准简介ACS标准(American Community Survey)是美国人口普查局(U.S. Census Bureau)进行的一项重要调查,旨在跟踪和了解美国社区的社会、经济和住房情况。
该调查采用随机抽样方法,涵盖了全美各地的市镇、县区和郡。
ACS标准自2005年开始实施,目前已成为衡量美国社会发展和政策制定的重要依据之一。
背景1.美国人口普查局简介–成立背景–职责和使命–数据来源和使用方式2.ACS标准的重要性–弥补数据滞后性–支持决策制定–提供社会经济描绘ACS标准的调查方法1.问卷设计–内容结构–问题选择和权重–数据可靠性和准确性2.抽样方法–地域抽样–个人抽样–数据覆盖和全国代表性3.调查工具和技术–邮寄调查–网络调查–访谈调查ACS标准的应用领域1.政府规划和决策–城市规划–社会福利政策–教育资源分配2.商业智能和市场分析–潜在客户调研–市场细分和定位–销售趋势预测3.学术研究和社会科学–人口迁移和流动性–经济增长和社会不平等–教育和就业趋势分析ACS标准的数据分析工具1.数据处理和清洗–缺失值处理–数据代码转换–数据匹配和整合2.数据可视化–条形图和饼图–散点图和折线图–地图和空间分析3.数据建模和预测–回归分析–聚类分析–时间序列预测ACS标准的未来发展1.数据更新和频率提高–数据滞后问题–实时调查技术–敏感性数据保护2.跨领域数据整合–跨部门数据共享–数据安全和隐私保护–多源数据整合和应用3.国际合作和标准统一–各国数据比较和参考–数据共享和交换–数据标准和质量管理结论ACS标准作为美国的重要社会经济调查之一,为政府、企业和学术界提供了丰富的数据资源和分析工具。
通过持续更新和改进,ACS标准将进一步适应多领域需求,并为更精确的决策制定和社会发展提供支持。
同时,国际合作和标准统一也将促进全球数据间的比较和共享,推动全球社会经济发展的可持续性。
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美国人口普查American census
For years, Jorge DelPinal's job as assistant chief of the Census Bureau's Population Division was to fit people into neat, distinct racial and ethnic
boxes: white, black, Hispanic, Asian or Native American. As the son of an
Anglo mother and a Hispanic father, however, he knew all along that the task
was not always possible.
For the 2000 decennial census, that will no longer be the case. For the first
time, the census forms will allow people to check off as many races as apply.
As a result, the Census Bureau should obtain a better picture of the extent of intermarriage in the United States. In the absence of such a direct method,
a few years ago veteran demographer Barry Edmonston used sophisticated mathematicalmodeling techniques to calculate how intermarriage is changing the face of the United States as part of an immigration study he directed for the National Research Council of the American Academy of Sciences. His research was summarized in a report entitled The New Americans: Economic, Demographic and Fiscal Effects of Immigration. But as the Canadian-born, white husband of sociologist Sharon Lee,a Chinese-American, Edmonston really needed no computer to understand thetransformation under way in this society. He and his family
are living, breathing participants. The face of America is changing -- literally.
As President Clinton has said, within 30 or 40 years, when there will be
no single race in the majority in the United States. But afoot behind the scenes
is another trend that, if handled carefully, could bring the country closer
together rather than drive it apart. This quiet demographic counter-revolution
is a dramatic upsurge in intermarriage. Edmonston's study projected that by 2050, 21 percent of the U.S. population will be of mixed racial or ethnic ancestry, up
from an estimate of seven percent today. Among third-generation Hispanic and Asian Americans, exogamy-marriage outside one's ethnic group or tribe-is at least
50 percent, he and others estimate. Exogamy remains much less prevalent among African Americans, but it has increased enormously, from about 1.5 percent in
the 1960s to eight to 10 percent today. Such a profound demographic shift
could take place while no one was watching because, officially, no one was watching. Federal agencies traditionally collected racial data using a formula'
one person, one race' similar to the time-honored voting principle. Thus, the Census Bureau could estimate that on census forms no more than two percent of
the population would claim to be multiracial. In the absence of a more straightforward count, no one could know for sure what the demographics are.。