context: There were 1,882 households of which 21.4% had children under the age of 18 living with them, 36.4% were Marriage living together, 9.7% had a female householder with no husband present, 3.6% had a male householder with no wife present, and 50.4% were non-families. 37.7% of all households were made up of individuals and 13% had someone living alone who was 65 years of age or older. The average household size was 2.20 and the average family size was 2.90.
question: Which groups in average are under 4 in size?
reference: household size, family size
candidate: family size