Social welfare function W: Rn-R gives social utility W(u1, u2,. un ). W is strictly increasing is socially optimal if it solves max Wu(a1), u2(a2),., un(n) st>Tis>w Proposition 1.29. If is SO, it is PO. I Proposition 1. 30. Suppose that preferences are continuous, strictly monotonic, and strictly convex. Then, for any PO allocation x* with >>0,v i, there exist ai

1. Producer Theory 1. Technology yi =input of good i, y =output of good i, i= yi-yi=net output, y yn) is a production plan Production possibility set Y=technologically feasible production plans yE Rn) y E Y is technologically efficient if there is no yE Y s.t. y>y

第一节复式记账 记账方法 使用特定的记账符号,按照一定的规 则,在账户中登记各种经济业务的技 术方法

小麦叶锈病是禾谷类锈病中分布最广、发生最普遍的一种小麦病害,全世界小麦种植区, 包括北美、欧洲、亚洲、澳洲、非洲等的许多国家都有发生。中国小麦叶锈病以西南和长江 流域一带发生较重,华北和东北部分麦区也较重。华北冬麦区1969、1973、1975和1979 年叶锈病大流行,东北春麦区1971、1973、1975和1980年中度流行,均造成相当大的经济 损失

苹果病害简介 苹果是我国的重要果树,病害是威胁苹果生产的主要障碍之一。据报道,苹果病害约有 100余中,按危害部位常分为果实病害、叶部病害、枝干病害和根部病害 果实病害中,常见且危害严重的有苹果果实轮纹病、炭疽病、霉心病、褐腐病和锈果病 等。苹果果实轮纹病是近年来苹果生产上最重要的烂果病,经常造成极其严重的经济损失, 某些感病品种如金冠和富士等,在发病严重年份采收时病果率可达50%以上,贮藏一个月 后烂果率会更高。炭疽病又称苦腐病,在全国各苹果产区均有发生,尤其以夏季高温、多雨、 潮湿地区最为严重,也是重要的果实病害之一

一、医用 二、食用 三、工业用 四、指示植物 五、农业用 六、观赏

Some Terminology o In the simple linear regression model where y=Bo+ Bx+ u, we typically refer to y as the a Dependent variable, or a Left-Hand Side Variable. or Explained variable, or Regressand

Assumptions of the classical Linear Model (Clm) e So far, we know that given the Gauss Markov assumptions, OLS IS BLUE e In order to do classical hypothesis testing we need to add another assumption(beyond the Gauss-Markov assumptions) Assume that u is independent of x,x2…,xk and u is normally distributed with zero mean and variance 0: u- Normal(0, 02) Economics 20- Prof anderson

Redefining variables Changing the scale of the y variable will lead to a corresponding change in the scale of the coefficients and standard errors. so no change in the significance or interpretation Changing the scale of one x variable will lead to a change in the scale of that coefficient and standard error, so no change in the significance or interpretation Economics 20- Prof anderson

What is Heteroskedasticity Recall the assumption of homoskedastic implied that conditional on the explanator variables the variance of the unobserved error u was constant If this is not true that is if the variance of u is different for different values of thex's. then the errors are heteroskedastic