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Final Review Introduction ot Econometrics,Fall 2020 Zhaopeng Qu Nanjing University 12/31/2020 Zhaopeng Qu (Nanjing University) Final Review 12/31/2020 1 / 17

Final Review - Introduction ot Econometrics,Fall 2020 · 2020. 12. 30. · Final Review Introduction ot Econometrics,Fall 2020 Zhaopeng Qu Nanjing University 12/31/2020 Zhaopeng Qu

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  • Final ReviewIntroduction ot Econometrics,Fall 2020

    Zhaopeng Qu

    Nanjing University

    12/31/2020

    Zhaopeng Qu (Nanjing University) Final Review 12/31/2020 1 / 17

  • Information

    Exam Time: 𝐽𝑎𝑛.10, 2021, 𝑀𝑜𝑛, 8 ∶ 00 − 10 ∶ 00Books and notes are not allowed. A calculator is an optional.

    You can also bring an paper English-Chinese dictionary ratherthan electronic one if you want use it.

    All questions are in English. And answers in either Chinese orEnglish or in both can be accepted.

    Time Management is very critical. Do not spend too muchtime on a single question.

    Zhaopeng Qu (Nanjing University) Final Review 12/31/2020 2 / 17

  • Review: Review Lecture 0

    What is econometrics?

    Data Structure:

    Cross sectionTimes seriesPool-Cross sectionsPanel Data

    Micro-Econometrics v.s Macro-Econometrics

    Zhaopeng Qu (Nanjing University) Final Review 12/31/2020 3 / 17

  • Review Lecture 1

    Review of Probability Theory

    Main Missions of Empirical Work: Causality v.s. Forecasting

    A framework of Causal Inference

    Rubin Causal ModelRandomized trial as the benchmarkRCT does not work in reality?

    Zhaopeng Qu (Nanjing University) Final Review 12/31/2020 4 / 17

  • Review Lecture 2

    Review of Basic Statistics

    LLW and CLTStatistical InferencePoint estimation: Estimator and EstimateThree Characteristics of an EstimatorProperties of the sample mean and the sample varianceHypothesis Testing and P-ValueConfidence Interval and significance levelHypothesis Tests for the Difference Between Two Means

    Randomized Controlled Trials

    Zhaopeng Qu (Nanjing University) Final Review 12/31/2020 5 / 17

  • Review Lecture 3

    Simple OLS:

    OLS estimator 𝛽R squares

    The Least Squares Assumptions:

    Assumption 1Assumption 2Assumption 3

    Properties of the OLS estimator

    The OLS estimator is unbiased, consistent and hasasymptotically normal sampling distribution.

    Zhaopeng Qu (Nanjing University) Final Review 12/31/2020 6 / 17

  • Review Lecture 4

    Multiple OLS Regression: Estimation

    OVB BiasPerfect multicollinearity: Assumption 4Interpretation of coefficientsPartitioned regression: proof unbiasedAdjusted R-Squres

    Zhaopeng Qu (Nanjing University) Final Review 12/31/2020 7 / 17

  • Review Lecture 5

    Statistical Inference of 𝛽

    standard error of 𝛽Hypothesis concerning 𝛽Confidence interval

    Multiple Regression: Hypotheses tests

    Heteroskedasticity & homoskedasticityTesting hypothesis on 2 or more coefficients: F-test

    Zhaopeng Qu (Nanjing University) Final Review 12/31/2020 8 / 17

  • Review Lecture 6: Nonlinear Regression

    Polynomials, Logarithmic transformations and Interactions

    How to explain these estimate coefficients?

    Zhaopeng Qu (Nanjing University) Final Review 12/31/2020 9 / 17

  • Review Lecture 7: Binary Dependent Variable

    LPM,Logit and Probit

    explain the estimate coefficientMarginal effectThe pseudo-R2

    Zhaopeng Qu (Nanjing University) Final Review 12/31/2020 10 / 17

  • Review Lecture 8

    Internal validity v.s External validity

    Threats to internal validity

    Omitted variables biasFunction form misspecificationMeasurement errorSimultaneous causalityMissing Data and Sample SelectionHeteroskedasticity and/or correlated error terms

    Zhaopeng Qu (Nanjing University) Final Review 12/31/2020 11 / 17

  • Review Lecture 9: Decompostion

    OB decomposition framework

    Reference group problem: adjusted-weight

    Zhaopeng Qu (Nanjing University) Final Review 12/31/2020 12 / 17

  • Review Lecture 10: Instrumental Variables

    Two assumptions

    Statistical properties of 2SLS estimator

    Checking Instrument Validity

    first stage: weak instrumentinstitutional backgroud to arguereduced form: exclusive restricionmore IVs: overidentification test

    Heterogeneous effect and LATE

    Zhaopeng Qu (Nanjing University) Final Review 12/31/2020 13 / 17

  • Review Lecture 11: Regression DiscontinuityDesign

    RDD: Basic Ideas and Types

    Basic assumptions

    Check Validity of RDD

    Zhaopeng Qu (Nanjing University) Final Review 12/31/2020 14 / 17

  • Review Lecture 12: Fixed Effects Model and DID

    Fixed effect: assumption and estimation

    DID: basic idea and assumption

    SCM: basic idea and assumption

    Zhaopeng Qu (Nanjing University) Final Review 12/31/2020 15 / 17

  • Closing Words

    Zhaopeng Qu (Nanjing University) Final Review 12/31/2020 16 / 17

  • Closing Words

    Zhaopeng Qu (Nanjing University) Final Review 12/31/2020 17 / 17