* do-file for Supplementary Exercise 2.59 of IPS7e
version 18 /* works also with versions 13-17 */

import delimited "R:\Chapter 2\ex02_059.csv"
* two separate plots
twoway (scatter time dist, sort), by(hand)
encode hand, g(Hand)
* two-part plot built by separate specification of two parts
twoway (scatter time dist if Hand==1) (scatter time dist if Hand==2)
twoway (scatter time dist if Hand==1) (scatter time dist if Hand==2) (lfit time dist if Hand==1) (lfit time dist if Hand==2)
* separate regressions
bysort hand: regress time dist