Context: There were 167,490 households of which 29.7% had children under the age of 18 living with them, 22.4% were married couples living together, 25.3% had a female householder with no husband present, 6.0% had a male householder with no wife present, and 46.4% were non-families. 39.5% of all households were made up of individuals and 10.7% had someone living alone who was 65 years of age or older. The average household size was 2.29 and the average family size was 3.11.

Question: Which groups in average are under 4 in size?

Answer:
family size