what is a simultaneous equation which variables are endogenous how to estimate how many variables in a simultaneous equation which equation is a relationship between z and the variables? which statement describes the difference between an endogenous and a concurrent equation? what is the relationship between a variable and a variable variable which statement is true about an equation that is changing at the same time? are z variables endogenous if the variable is changing, which type of relationship is possible? which is an endogenous relationship that is always changing? what relationship is used to find the relationship between the variables in a single equation which of the following is an endogenous equation? what's the relationship between two variables in a simultaneous equation which equation is a simultaneous equation is z variable an endogenous variable which variable is the difference between a fixed or endogenous variable? what are the relationships between variable y and z what's the relationship between both variables? what variables are always changing simultaneously what is the relationship between y, z, and z in a parallel equation