How do you create a single mother variable

I want to find out how many single mothers there are in NYC in relation to race and ethnicity

It sounds like you are going to want to explore your options within IPUMS USA. For example, there is a variable available for marital status, MARST. You could use this in combination with SEX to define your population of “single women”. Furthermore, you can find the number of a person’s own children living in a household using NCHILD.

We have a collection of race and ethnicity variables available. To identify NYC, I would suggest you explore the available geographic variables such as PUMA, METAREA/METAREA2013 and COUNTY.