About: http://webisa.webdatacommons.org/61472527

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	What you have there is a data frame and at least one of the columns you are trying to work with is a factor.
http://www.w3.org/ns/prov#wasQuotedFrom	stackoverflow.com