This is based on a Bhalotra and Venkatramani (2013) working paper. A researcher is interested in studying the effect of safe water on child mortality. She uses the clean water program, Programa de Agua Limpia (PAL), to study this issue. PAL was launched in Mexico in 1991, following a sudden emergence of cholera in Central America. Some towns were given access to PAL funds to chlorinate the water. Other towns did not receive those funds. The allocation of funds was not random. For each town in Mexico, the researcher compiles the Child Mortality Rate (per 1,000 children), CMR, for the period 19851990 and the mortality rate for the period 1991-1996 and sets up a difference in difference analysis. In this analysis each town is observed twiceonce before and once after PAL is introduced. Let Aftert be an indicator variable equal to 1 if the observation corresponds to the period 19911996. Let PAL,- be a dummy variable equal to 1 if the observation corresponds to a town that received PAL funds. Create a 3 by 3 difference in difference matrix and fill it based on the coefficients you see below. Enter the values in each cell. PAL No PAL Difference Period 1991- 1 -0.81 1. 1 1995 8 Period 1985- 0.32 1990 2.55 2.23 Difference '155 '0-42 -1.43 What is the impact of the PAL chlorination policy on child mortality rate? The policy reduced mortality by 320 deaths per 1,000 children