政治大學中山所共同選修 課程名稱： 社會科學計量方法與統計－計量方法 Methodology of Social Sciences 授課內容： Introduction to Econometrics 日期： 2003 年 9 月 24 日

政治大學 中山所共同選修 黃智聰 一、重要性 Ex ： 服務年資

政治大學 中山所共同選修 黃智聰 gends2萬2萬 3萬3萬 4 萬以上 男 女 Income Show the relationship b/w tow variable

政治大學 中山所共同選修 黃智聰 But empirical model:control other variables and examines the pure influence of one variable on the other! Cross-table ＝＞ (1) ignore other variables (2)can ’ t tell anything regarding casuality. 當選 不當選 國 民 親

政治大學 中山所共同選修 黃智聰 二、 why study Econometics Theory practice, investigate, examine. Applications: accounting, finace, marlceting, mangement, social scientists, (history, political science, sociology)., forestry, agricultural economics.

政治大學 中山所共同選修 黃智聰 三、 What is Econometrics Relationship b/w variables C d =f(i) q d =f(P,P s,P c,i) Econometrics is about how we can use economic, business or socail science theory and data, along witj tools from statistics, to answer “ how much ” type questions

政治大學 中山所共同選修 黃智聰 How much a change in one variable affects another parameter. Parameter: unknown, estimated using a sample of data when formulating economic policies. The importance of Good econometrics: bias or error Ex:uniformed police violent crime Advertising voters Advertising sales Tuition enrollment 紅包 當選機率

政治大學 中山所共同選修 黃智聰 四、 Econometric Model q d =f(p, p s, p c, i) + e Random error : accounts for the many factors that affect scales that we have omitted from this simple model. The Specification of the econometric model. linear function: f(p,p s,p c,i)=  1 +  2 p+  3 P s +  4 P c +  5 i  q d =  1 +  2 p+  3 P s +  4 P c +  5 i+e I ’ m a random error!!!

政治大學 中山所共同選修 黃智聰 五、 Experimental Data Design an experiment obtain observations or sample information provide insight about the unknown parameters repeating the experiment T times create a sample of T sample observation

政治大學 中山所共同選修 黃智聰 ex: p =25,000 Accords 是否為 KMT P s =25,000 Maximas 競選經費 P c =1.35 gasoline 地區 i =42,000 income 是否連任 得票數 q d :Quantity demanded of Accords repeating this process to obtain experimental data

政治大學 中山所共同選修 黃智聰 六、 Nonexperimental Data Data are collected for administrative by government Time-series form : data collected over discrete intervals of time Cross section form : data collected over sample units in a particular time period *panel data form : data that follow individual micro-unit over time.

政治大學 中山所共同選修 黃智聰 There data may be collected at various levels of aggregation: *micro : data collected on individual decision making units such as individuals, households, or firms *macro : data resulting from a pooling or aggregating over individuals, households or firms at the local, state or national levels.

政治大學 中山所共同選修 黃智聰 Flow or stock *flow : outcome measures over a period of time, such as the consumption of gasoline during the last quarter of 1999 *stock: outcome measured at a particular point in time, such as the quantity of crude oil held by Chevron in its US storage tanks April 1,1999

政治大學 中山所共同選修 黃智聰 quantitative or qualitative *quantitative : outcome may be expressed as number or some transformation of them *qualitative : outcome that are of an “ either-or ” situation.

政治大學 中山所共同選修 黃智聰 VII. Statistical Inference We want to infer or loan southing about the real world by analyzing a sample of data. 1. Estimating economic parameters using econometric method 2. predicting outcomes 3.Testing economic hypotheses

政治大學 中山所共同選修 黃智聰 VIII. A Research Format 1. It all starts with a problem or question 2.Theory give us a way of thinking about the problem. 3.The working model leads to an econometric model we choose a functional form and make some assumptions about the nature of the error term 4.Sample data are obtained, and a desirable method of statistical analysis chosen, based on our initial assumptions and our understanding of how the data were collected.

政治大學 中山所共同選修 黃智聰 5.Estimates of the unknown parameters are obtained with the help of a statistical software package, predictions are made and hypothesis fest are performed. 6.Model diagnostics are performed to check to validity of assumptions we have made. ex: were all of the right hand-side explanatory variables relevant? Was the correct functional form used? 7. The consequence and the implications of the empirical results are analyzed and evaluated. What are their policy-choice implications? What remaining questions might be answered with further study or new and better data?