I have a picklist for ethnicity sub category, and I am trying to create an Ethnicity formula field which automatically updates depending on the picklist value. 
An example of the formula:
IF (Ethnicity_Sub_Category__c>= Vietnamese, "Asian", 
IF (Ethnicity_Sub_Category__c>= Asian Other, "Asian"

Error message:
Error: Syntax error. Found 'Asian'

I tried a few other formulas but also received Error: Field Ethnicity_Sub_Category__c is a picklist field. Picklist fields are only supported in certain functions.

Is there a way to do this?

Thanks in advance

I have a picklist for ethnicity sub category, and I am trying to create an Ethnicity formula field which automatically updates depending on the picklist value. 
An example of the formula:
IF (Ethnicity_Sub_Category__c>= Vietnamese, "Asian", 
IF (Ethnicity_Sub_Category__c>= Asian Other, "Asian"

Error message:
Error: Syntax error. Found 'Asian'

I tried a few other formulas but also received Error: Field Ethnicity_Sub_Category__c is a picklist field. Picklist fields are only supported in certain functions.

Is there a way to do this?

Thanks in advance