Can Riots affect football games attendance? Attendancei= 0 + 1 Riot turnouti + i Attendancei is the

Can Riots affect football games attendance? Attendancei= β0 + β1 Riot turnouti + εi Attendancei is the stadium attendance in city I in 2020 whilst Riot turnouti Is the number of people that went to riots in city i on the 7th of jan 2019 (Day of BLM protests)

 

There were major snow storms in the US on the 7th on jan 2019. Consider this snow as an instrument for riot protests, How can you test if the snow satisfies the first stage condition?