We're learning about instrumental variable estimators and I just want to confirm my logic in these answers. Really appreciate the help!
a. True- If this happens and these variables are omitted, it will result in omitted variable bias.
b. False- having an equal amount of variables doesn't affect how the parameters are identified.
c. True- You can only use variables as instruments if they aren't included in your model.
d. True- Deriving these relationships will still result in linear variables.
Thanks again for the help