We will continue to improve the company's internal control system, and steady improvement in ability to manage and control, optimize business processes, to ensure smooth processes, responsibilities in place; to further strengthen internal controls, play a control post independent oversight role of evaluation complying with third-party responsibility; to actively make use of internal audit tools detect potential management, streamline, standardize related transactions, strengthening operations in accordance with law. Deepening the information management to ensure full communication \o constantly perfect ERP, and BFS++, and PI, and MIS, and SCM, information system based construction, full integration information system, achieved information resources shared; to expand Portal system application of breadth and depth, play information system on enterprise of Assistant role; to perfect daily run maintenance operation of records, promote problem reasons analysis and system handover; to strengthening BFS++, and ERP, and SCM, technology application of training, improve employees application information system of capacity and level. Humanistic care to ensure \To strengthening Humanities care, continues to foster company wind clear, and gas are, and heart Shun of culture atmospherestrengthening love helped trapped, care difficult employees; carried out style activities, rich employees life; strengthening health and labour protection, organization career health medical, control career against; continues to implementation psychological warning prevention system, training employees health of character, and stable of mood and enterprising of attitude, created friendly fraternity of Humanities environment. o strengthen risk management, ensure that the business of \d business plans management, will business business plans cover to all level, ensure the business can control in control; to close concern financial, and coal electric linkage, and energy-saving scheduling, national policy trends, strengthening track, active should; to implementation State-owned assets method, further specification business financial management; to perfect risk tube control system, achieved risk recognition, and measure, and assessment, and report, and control feedback of closed ring management, improve risk prevention capacity. o further standardize trading, and strive to achieve \ding to law, standardize and fair.\nce management, to ensure that potential employees \o fly\o strengthen performance management, process control, enhance employee evaluation and levels of effective communication to improve performance management. o further quantify and refine employee standards ... Work, full play party, and branch, and members in \se\n the of core role, and fighting fortress role and pioneer model role; to continues to strengthening \good\dership construction, full play levels cadres in enterprise development in the第1章
解决问题的办法
1.1（一）理想的情况下，我们可以随机分配学生到不同尺寸的类。也就是说，每个学生被分配一个不同的类的大小，而不考虑任何学生的特点，能力和家庭背景。对于原因，我们将看到在第2章中，我们想的巨大变化，班级规模（主题，当然，伦理方面的考虑和资源约束）。
（二）呈负相关关系意味着，较大的一类大小是与较低的性能。因为班级规模较大的性能实际上伤害，我们可能会发现呈负相关。然而，随着观测数据，还有其他的原因，我们可能会发现负相关关系。例如，来自较富裕家庭的儿童可能更有可能参加班级规模较小的学校，和富裕的孩子一般在标准化考试中成绩更好。另一种可能性是，在学校，校长可能分配更好的学生，以小班授课。或者，有些家长可能会坚持他们的孩子都在较小的类，这些家长往往是更多地参与子女的教育。
（三）鉴于潜在的混杂因素 - 其中一些是第（ii）上市 - 寻找负相关关系不会是有力的证据，缩小班级规模，实际上带来更好的性能。在某种方式的混杂因素的控制是必要的，这是多元回归分析的主题。
1.2（一）这里是构成问题的一种方法：如果两家公司，说A和B，相同的在各方面比B公司à用品工作培训之一小时每名工人，坚定除外，多少会坚定的输出从B公司的不同？
（二）公司很可能取决于工人的特点选择在职培训。一些观察到的特点是多年的教育，多年的劳动力，在一个特定的工作经验。企业甚至可能歧视根据年龄，性别或种族。也许企业选择提供培训，工人或多或少能力，其中，“能力”可能是难以量化，但其中一个经理的相对能力不同的员工有一些想法。此外，不同种类的工人可能被吸引到企业，提供更多的就业培训，平均，这可能不是很明显，向雇主。
（iii）该金额的资金和技术工人也将影响输出。所以，两家公司具有完全相同的各类员工一般都会有不同的输出，如果他们使用不同数额的资金或技术。管理者的素质也有效果。
（iv）无，除非训练量是随机分配。许多因素上市部分（二）及（iii）可有助于寻找输出和培训的正相关关系，即使不在职培训提高工人的生产力。
1.3没有任何意义，提出这个问题的因果关系。经济学家会认为学生选择的混合学习和工作（和其他活动，如上课，休闲，睡觉）的基础上的理性行为，如效用最大化的约束，在一个星期只有168小时。然后我们可以使用统计方法来衡量之间的关联学习和工作，包括回归分析，我们覆盖第2章开始。但我们不会声称一个变量“使”等。他们都选择学生的变量。
第2章
解决问题的办法
of backbone backbone role; to full strengthening members youth work, full play youth employees in company development in the of force role; to improve independent Commission against corruption work level, strengthening on enterprise business key link of effectiveness monitored. , And maintain stability. To further strengthen publicity and education, improve the overall legal system. We must strengthen safety management, establish and improve the education, supervision, and evaluation as one of the traffic safety management mechanism. o conscientiously sum up the Olympic security controls, promoting integrated management to a higher level, higher standards, a higher level of development. Employees, today is lunar calendar on December 24, the ox Bell is about to ring, at this time of year, we clearly feel the pulse of the XX power generation company to flourish, to more clearly hear XX power generation companies mature and symmetry breathing. Recalling past oneanother across a railing, we are enthusiastic and full of confidence. Future development opportunities, we more exciting fight more spirited. Employees, let us together across 2013 full of challenges and opportunities, to create a green, low-cost operation, full of humane care of a world-class power generation company and work hard! The occasion of the Spring Festival, my sincere wish that you and the families of the staff in the new year, good health, happy, happyWe will continue to improve the company's internal control system, and steady improvement in ability to manage and control, optimize business processes, to ensure smooth processes, responsibilities in place; to further strengthen internal controls, play a control post independent oversight role of evaluation complying with third-party responsibility; to actively make use of internal audit tools detect potential management, streamline, standardize related transactions, strengthening operations in accordance with law. Deepening the information management to ensure full communication \o constantly perfect ERP, and BFS++, and PI, and MIS, and SCM, information system based construction, full integration information system, achieved information resources shared; to expand Portal system application of breadth and depth, play information system on enterprise of Assistant role; to perfect daily run maintenance operation of records, promote problem reasons analysis and system handover; to strengthening BFS++, and ERP, and SCM, technology application of training, improve employees application information system of capacity and level. Humanistic care to ensure \To strengthening Humanities care, continues to foster company wind clear, and gas are, and heart Shun of culture atmosphere; strengthening love helped trapped, care difficult employees; carried out style activities, rich employees life; strengthening health and labour protection, organization career health medical, control career against; continues to implementation psychological warning prevention system, training employees health of character, and stable of mood and enterprising of attitude, created friendly fraternity of Humanities environment. o strengthen risk management, ensure that the business of \d business plans management, will business business plans cover to all level, ensure the business can control in control; to close concern financial, and coal electric linkage, and energy-saving scheduling, national policy trends, strengthening track, active should; to implementation State-owned assets method, further specification business financial management; to perfect risk tube control system, achieved risk recognition, and measure, and assessment, and report, and control feedback of closed ring management, improve risk prevention capacity. o further standardize trading, and strive to achieve \ding to law, standardize and fair.\nce management, to ensure that potential employees \o fly\o strengthen performance management, process control, enhance employee evaluation and levels of effective communication to improve performance management. o further quantify and refine employee standards ... Work, full play party, and branch, and members in \se\n the of core role, and fighting fortress role and pioneer model role; to continues to strengthening \good\dership construction, full play levels cadres in enterprise development in the2.1（I）的收入，年龄，家庭背景（如兄弟姐妹的人数）仅仅是几个可能性。似乎每个可以与这些年的教育。 （收入和教育可能是正相关，可能是负相关，年龄和受教育，因为在最近的同伙有妇女，平均而言，更多的教育和兄弟姐妹和教育的人数可能呈负相关）。
（ii）不会（i）部分中列出的因素，我们与EDUC。因为我们想保持这些因素不变，它们的误差项的一部分。但是，如果u与EDUC那么E（U | EDUC）0，所以SLR.4失败。
2.2方程Y =0 +1X + U，加减0的右边，得到y =（0 +0）+1X +（U0）。调用新的错误E =ü0，故E（E）= 0。新的拦截0 +0，但斜率仍然是1。 2.3（一）让易= GPAI，XI = ACTI，和n = 8。 = 25.875，= 3.2125，（十一 - ）（艺 - ）= 5.8125，（十一 - ）2 = 56.875。从公式（2.9），我们得到了坡度为= 5.8125/56.875 0.1022，四舍五入至小数点后四个地方。 （2.17）= - 3.2125 - 0.1022 25.875 0.5681。因此，我们可以这样写
= 0.5681 + 0.1022 ACT 每组8只。
拦截没有一个有用的解释，因为使不接近零的人口的利益。 ，如果ACT是高5点，增加0.1022（5）= .511。
（二）观察数i和GPA的拟合值和残差 - 四舍五入至小数点后四位 - 随着于下表：
íGPA
1 2.8 2.7143 0.0857 2 3.4 3.0209 0.3791 3 3.0 3.2253 - 0.2253 4 3.5 3.3275 0.1725 5 3.6 3.5319 0.0681 6 3.0 3.1231 - 0.1231 7 2.7 3.1231 - 0.4231 8 3.7 3.6341 0.0659
您可以验证的残差，表中报告，总结到.0002，这是非常接近零，由于固有的舍入误差。
（ⅲ）当ACT = 20 = 0.5681 + 0.1022（20）2.61。
（iv）本残差平方和，大约是0.4347（四舍五入至小数点后四位），正方形的总和，（YI - ）2，大约是1.0288。因此，R-平方的回归
R2 = 1 - SSR / SST 1 - （.4347/1.0288）.577的。
of backbone backbone role; to full strengthening members youth work, full play youth employees in company development in the of force role; to improve independent Commission against corruption work level, strengthening on enterprise business key link of effectiveness monitored. , And maintain stability. To further strengthen publicity and education, improve the overall legal system. We must strengthen safety management, establish and improve the education, supervision, and evaluation as one of the traffic safety management mechanism. o conscientiously sum up the Olympic security controls, promoting integrated management to a higher level, higher standards, a higher level of development. Employees, today is lunar calendar on December 24, the ox Bell is about to ring, at this time of year, we clearly feel the pulse of the XX power generation company to flourish, to more clearly hear XX power generation companies mature and symmetry breathing. Recalling past oneanother across a railing, we are enthusiastic and full of confidence. Future development opportunities, we more exciting fight more spirited. Employees, let us together across 2013 full of challenges and opportunities, to create a green, low-cost operation, full of humane care of a world-class power generation company and work hard! The occasion of the Spring Festival, my sincere wish that you and the families of the staff in the new year, good health, happy, happyWe will continue to improve the company's internal control system, and steady improvement in ability to manage and control, optimize business processes, to ensure smooth processes, responsibilities in place; to further strengthen internal controls, play a control post independent oversight role of evaluation complying with third-party responsibility; to actively make use of internal audit tools detect potential management, streamline, standardize related transactions, strengthening operations in accordance with law. Deepening the information management to ensure full communication \o constantly perfect ERP, and BFS++, and PI, and MIS, and SCM, information system based construction, full integration information system, achieved information resources shared; to expand Portal system application of breadth and depth, play information system on enterprise of Assistant role; to perfect daily run maintenance operation of records, promote problem reasons analysis and system handover; to strengthening BFS++, and ERP, and SCM, technology application of training, improve employees application information system of capacity and level. Humanistic care to ensure \To strengthening Humanities care, continues to foster company wind clear, and gas are, and heart Shun of culture atmospherestrengthening love helped trapped, care difficult employees; carried out style activities, rich employees life; strengthening health and labour protection, organization career health medical, control career against; continues to implementation psychological warning prevention system, training employees health of character, and stable of mood and enterprising of attitude, created friendly fraternity of Humanities environment. o strengthen risk management, ensure that the business of \d business plans management, will business business plans cover to all level, ensure the business can control in control; to close concern financial, and coal electric linkage, and energy-saving scheduling, national policy trends, strengthening track, active should; to implementation State-owned assets method, further specification business financial management; to perfect risk tube control system, achieved risk recognition, and measure, and assessment, and report, and control feedback of closed ring management, improve risk prevention capacity. o further standardize trading, and strive to achieve \ding to law, standardize and fair.\nce management, to ensure that potential employees \o fly\o strengthen performance management, process control, enhance employee evaluation and levels of effective communication to improve performance management. o further quantify and refine employee standards ... Work, full play party, and branch, and members in \se\n the of core role, and fighting fortress role and pioneer model role; to continues to strengthening \good\dership construction, full play levels cadres in enterprise development in the
因此，约57.7％的GPA的变化解释使学生在这个小样本。
2.4（I）的CIGS = 0，预测出生体重是119.77盎司。当CIGS = 20，= 109.49。这是关于一个8.6％的降幅。
（ii）并非必然。还有许多其他的因素，可以影响新生儿的体重，尤其是整体健康的母亲和产前护理质量。这些可以与吸烟密切相关，在分娩期间。此外，如咖啡因消费的东西可以影响新生儿的体重，也可能与吸烟密切相关。
（三）如果我们想预测125 bwght，然后CIGS =（125 - 119.77）/（ - .524）-10.18，或约-10香烟！当然，这完全是无稽之谈，并表明会发生什么，当我们试图预测复杂，出生时体重只有一个单一的解释变量的东西。最大的预测出生体重必然是119.77。然而，近700个样品中有出生出生体重高于119.77。
（四）1,176 1,388名妇女没有在怀孕期间吸烟，或约84.7％。因为我们使用的唯一的的CIGS解释出生体重，我们只有一个预测出生体重在CIGS = 0。预测出生体重必然是大致中间观察出生体重在CIGS = 0，所以我们会根据预测高出生率。
2.5（i）本截距意味着，，当INC = 0，缺点被预测为负124.84美元。 ，当然，这不可能是真实的，反映了这一事实，在收入很低的水平，这个消费函数可能是一个糟糕的预测消费。另一方面，在年度基础上，124.84美元至今没有从零。
（二）只需插上30,000入公式：= -124.84 + .853（30,000）= 25,465.16元。
（iii）该MPC和APC的是在下面的图表所示。尽管截距为负时，样品中的最小的APC是正的。图开始以每年1,000元（1970美元）的收入水平。
2.6（i）同意。如果生活密切焚化炉抑制房价过快上涨，然后越远，增加住房价格。
（ii）若选择的城市定位在一个地区焚化炉远离更昂贵的街区，然后登录（区）呈正相关，与房屋质量。这将违反SLR.4，OLS估计是有失偏颇。
（三）大小的房子，浴室的数量，很多的大小，年龄，家庭，居委会（包括学校质量）质量，都只是极少数的因素。正如前面提到的（ii）部分，这些肯定会被分派[日志（DIST）]的相关性。
2.7（一）当我们条件的公司在计算的期望，成为一个常数。所以E（U | INC）= E（E | INC）= E（E | INC）= 0，因为E（E | INC）= E（E）= 0。
（2）同样，当我们条件的公司在计算方差，成为一个常数。所以VAR（U | INC）= VAR（E | INC）=（）2VAR（E | INC）INC，因为VAR（E | INC）=。
（三）家庭收入低没有对消费有很大的自由裁量权，通常情况下，一个低收入的家庭必须花
of backbone backbone role; to full strengthening members youth work, full play youth employees in company development in the of force role; to improve independent Commission against corruption work level, strengthening on enterprise business key link of effectiveness monitored. , And maintain stability. To further strengthen publicity and education, improve the overall legal system. We must strengthen safety management, establish and improve the education, supervision, and evaluation as one of the traffic safety management mechanism. o conscientiously sum up the Olympic security controls, promoting integrated management to a higher level, higher standards, a higher level of development. Employees, today is lunar calendar on December 24, the ox Bell is about to ring, at this time of year, we clearly feel the pulse of the XX power generation company to flourish, to more clearly hear XX power generation companies mature and symmetry breathing. Recalling past oneanother across a railing, we are enthusiastic and full of confidence. Future development opportunities, we more exciting fight more spirited. Employees, let us together across 2013 full of challenges and opportunities, to create a green, low-cost operation, full of humane care of a world-class power generation company and work hard! The occasion of the Spring Festival, my sincere wish that you and the families of the staff in the new year, good health, happy, happyWe will continue to improve the company's internal control system, and steady improvement in ability to manage and control, optimize business processes, to ensure smooth processes, responsibilities in place; to further strengthen internal controls, play a control post independent oversight role of evaluation complying with third-party responsibility; to actively make use of internal audit tools detect potential management, streamline, standardize related transactions, strengthening operations in accordance with law. Deepening the information management to ensure full communication \o constantly perfect ERP, and BFS++, and PI, and MIS, and SCM, information system based construction, full integration information system, achieved information resources shared; to expand Portal system application of breadth and depth, play information system on enterprise of Assistant role; to perfect daily run maintenance operation of records, promote problem reasons analysis and system handover; to strengthening BFS++, and ERP, and SCM, technology application of training, improve employees application information system of capacity and level. Humanistic care to ensure \To strengthening Humanities care, continues to foster company wind clear, and gas are, and heart Shun of culture atmosphere; strengthening love helped trapped, care difficult employees; carried out style activities, rich employees life; strengthening health and labour protection, organization career health medical, control career against; continues to implementation psychological warning prevention system, training employees health of character, and stable of mood and enterprising of attitude, created friendly fraternity of Humanities environment. o strengthen risk management, ensure that the business of \d business plans management, will business business plans cover to all level, ensure the business can control in control; to close concern financial, and coal electric linkage, and energy-saving scheduling, national policy trends, strengthening track, active should; to implementation State-owned assets method, further specification business financial management; to perfect risk tube control system, achieved risk recognition, and measure, and assessment, and report, and control feedback of closed ring management, improve risk prevention capacity. o further standardize trading, and strive to achieve \ding to law, standardize and fair.\nce management, to ensure that potential employees \o fly\o strengthen performance management, process control, enhance employee evaluation and levels of effective communication to improve performance management. o further quantify and refine employee standards ... Work, full play party, and branch, and members in \se\n the of core role, and fighting fortress role and pioneer model role; to continues to strengthening \good\dership construction, full play levels cadres in enterprise development in the费在食品，服装，住房，和其他生活必需品。收入高的人有更多的自由裁量权，有些人可能会选择更多的消费，而其他更节省。此酌情权，建议在收入较高的家庭储蓄之间的更广泛的变异。
第2.8（i）从方程（2.66），
= /。
堵在义=0 +1xi + UI给人
= /。
标准代数后，分子可以写为 。
把这个分母显示，我们可以写
=0 / +1 + /。
西安条件，我们有
E（）=0 / +1
因为E（UI）对于所有的i = 0。因此，偏置在这个方程中的第一项由下式给出。这种偏见显然是零，当0 = 0。也为零时，= 0，= 0这是相同的。在后者的情况下，通过原点的回归是回归截距相同。
（ii）从最后一个表达式部分（i）我们有，有条件兮，
（VAR）= VAR = == /。
（iii）由（2.57），VAR（）= 2 /。从心领神会，，所以无功（）：VAR（）。看，这是一种更直接的方式来写，这是小于除非= 0 =。
（ⅳ）对于一个给定的样本大小，偏置的增加（保持在固定的总和）的增加。但增加的方差相对增加（VAR）。偏置也是小的，小的时候。因此，无论是我们优选的平均平方误差的基础上取决于大小，和n（除的大小）。
2.9（i）我们按照提示，注意到=（样本均值为C1义的样本平均）=。当我们：回归c1yi c2xi（包括截距）我们使用公式（2.19）获得的斜率：
（2.17），我们得到的截距=（C1） - （C2）=（C1） - [（C1/C2）]（C2）= C1（ - ）= C1），因为拦截从回归毅喜（ - ）。
of backbone backbone role; to full strengthening members youth work, full play youth employees in company development in the of force role; to improve independent Commission against corruption work level, strengthening on enterprise business key link of effectiveness monitored. , And maintain stability. To further strengthen publicity and education, improve the overall legal system. We must strengthen safety management, establish and improve the education, supervision, and evaluation as one of the traffic safety management mechanism. o conscientiously sum up the Olympic security controls, promoting integrated management to a higher level, higher standards, a higher level of development. Employees, today is lunar calendar on December 24, the ox Bell is about to ring, at this time of year, we clearly feel the pulse of the XX power generation company to flourish, to more clearly hear XX power generation companies mature and symmetry breathing. Recalling past oneanother across a railing, we are enthusiastic and full of confidence. Future development opportunities, we more exciting fight more spirited. Employees, let us together across 2013 full of challenges and opportunities, to create a green, low-cost operation, full of humane care of a world-class power generation company and work hard! The occasion of the Spring Festival, my sincere wish that you and the families of the staff in the new year, good health, happy, happy