PII: 0304-4076(87)90041-8deaton/downloads/Estimating... · 2009-02-13 · has an expectation of...
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PII: 0304-4076(87)90041-8deaton/downloads/Estimating... · 2009-02-13 · has an expectation of zero within the cluster and is uncorrelated with all other variables, Inx and z, but