Stationary Stochastic Process e A stochastic process is stationary if for every collection of time indices 11 e Thus, stationarity implies that the x,'s are dentically distributed and that the nature of any correlation between adjacent terms is

Functional form e We' ve seen that a linear regression can really fit nonlinear relationships 2 Can use logs on RHS, LHS or both Can use quadratic forms ofx's Can use interactions ofx's e How do we know if we've gotten the right functional form for our model? Economics 20- Prof anderson

Dummy variables a dummy variable is a variable that takes on the value l or o Examples: male(= 1 if are male, O otherwise), south(=l if in the south, 0 otherwise), etc dummy variables are also called binar variables. for obvious reasons Economics 20- Prof anderson

Consistency e Under the Gauss-Markov assumptionS OLS IS BLUE, but in other cases it wont always be possible to find unbiased estimators o In those cases, we may settle for estimators that are consistent, meaning as n→>∞,the distribution of the estimator collapses to the parameter value Economics 20- Prof anderson

Parallels with Simple regression Bo is still the intercept B, to Bk all called slope parameters u is still the error term(or disturbance) Still need to make a zero conditional mean assumption, so now assume that E(lx,x2…,x)=0 Still minimizing the sum of squared residuals. so have k+l first order conditions Economics 20- Prof anderson

Why study econometrics? Rare in economics(and many other areas without labs! ) to have experimental data Need to use nonexperimental. or observational data to make inferences eImportant to be able to apply economic theory to real world data Economics 20- Prof. Anderson

其他蔬菜病害 我国蔬菜种类很多,除了上述的十字花科、茄科、葫芦科和豆科外,还有芹菜、胡 萝卜、菠菜、莴苣、葱、韭菜、大蒜、姜、洋葱、芦笋、黄花菜以及各种蘑菇等。病害 仍然是威胁这些蔬菜生产的重要障碍之一,有些病害如芹菜斑枯病和早疫病,葱紫斑病 和霜霉病,姜的腐烂病,韭菜灰霉病以及多种蘑菇病害常常造成严重的经济损失,及时 有效地防治这些病害具有重要意义

桃、杏、李褐腐病 Stone fruits brown rot 褐腐病又名菌核病、果腐病、实腐病等。1796年最早记载,是一种世界性分布的病害。 可寄生在桃、杏、李、樱桃、梅等核果类果树上,引起果腐、花腐和叶枯。我国从南到北各 桃、杏、李产区均有发生。在核果类果树中以桃受害较重,江淮流域,江苏、浙江和山东每 年都有发生,北方桃园则多在多雨年份发生流行。褐腐病在春季开花展叶期如遇低温多雨, 引起严重的花腐和叶枯:在生长后期如遇多雨潮湿天气,引起果腐,使果实丧失经济价值 除在果园发生外,在运输

玉米丝黑穗病是玉米产区的重要穗部病害,国内外的玉米产区几乎均有发生。1919年 中国东北首次报道,现已遍及全国,尤其以东北、西北、华北和南方冷凉山区的连作玉米田 块发病较重,发病率一般在2%8%之间,个别重病地块发病率高达60%70%以上,造成严重 的经济损失

• 可持续发展 – 定义与背景 – 内涵与原则 • 可持续发展能力建设 – 能力建设与保障体系 • 城市与城市可持续发展 – 城市的特点 – 城市可持续发展的定义 • 城市环境和可持续发展指标 –案例 –城市指标的发展现状评析 –经济指标的考核—GDP？？ • 城市生态可持续发展 –特点与基本原则 –实现途径