create_equation: Create Regression Equation for Demand Estimation
In lachlandeer/demandr: Nested Logit Demand Estimation with Aggregate Market Shares

Create Regression Equation for Demand Estimation

1 2	create_equation(market_ids, product_id, market_share, outside_share, exog_charac, price, nest_shares, marketFE, productFE, instruments = NULL)

`market_ids`	List of variables contaning market identifiers
`market_share`	Variable containing product market shares, as a character string
`outside_share`	Variable containing outside market shares, as a character string
`exog_charac`	Vector of exogenous product characteristic variables, as a character vector
`price`	Variable containing market price, as a character string
`nest_shares`	Vector of nest share variables, as a character vector
`marketFE`	Character string of which market fixed effects to contain, takes value "both", "geog" or "time"
`instruments`	Vector of instrument names, as a character vector