Hi everyone. I am new to this site so please bear with me.

I am running a regression of property value against several house characteristics such as the number of bedrooms, bathrooms etc. One of the variables is 'propertysize'.

When collecting data for 'propertysize', some observations had a numerical value available in metres squared such as '100' whilst some observations had no number available so I had to estimate whether the property was 'small', 'medium', or 'large'. I collected all observations under the same variable 'propertysize'.

I want to run several regressions.

a) a regression where 'propertysize' only includes the numbers, thus removing my estimates
b) a regression where 'propertysize' only includes the original 'small', 'medium' and 'large' estimates I made, thus removing the numerical data
c) a regression where the numerical values are transformed to one of the size categories 'small', 'medium' and 'large'. So between the size of 0-65 metres squared a property is classed as 'small', 65-100 is 'medium', and >100 is 'large'. These transformed numbers would then be in the same format as my estimates and a regression would be run on the categories.

I have been succesfsul in part a).

However, I cannot find a method to work b) or c).