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Nonrandom Sampling and Tobit Models . ECON 721. Different Types of Sampling. Random sampling Censored sampling Truncated sampling Nonrandom Exogenous stratified Endogenous stratified Choice-based . Tobit Models. Main reference: Amemiya, Chapter 10. Type I Tobit Model.
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Nonrandom Sampling and Tobit Models ECON 721
Different Types of Sampling • Random sampling • Censored sampling • Truncated sampling • Nonrandom • Exogenous stratified • Endogenous stratified • Choice-based
Tobit Models • Main reference: Amemiya, Chapter 10
Type I Tobit Model • Tobin’s (1958) example – expenditure on a durable good only observed if expenditure exceeds the minimum price available.
Truncated Type I Tobit • Only observe data for people who purchased the good (e.g. gather data at appliance store)
Ways of Estimating Tobit Model • MLE • If censored, estimating probit and get coefficients up to scale • By OLS using results for conditional means of truncated normal random variables
Heckman’s female labor supply model (explains choice of H as well)
Estimation • MLE • Two-step method