# Elementary Statistics

by jkaufman jefftk1 min read5th Dec 2019No comments

# 12

Our elementary school has a directory listing kids and parents, and since we live in the future it's a spreadsheet, which means I can count things. A typical family at this K-5 school has one child enrolled (76%). The child has two parents (96%) with different last names (59%), but they share a last name with at least one parent (89%). The parents don't share email addresses (95%) or phone numbers (97%), do use gmail (72%), and do have Boston area codes (68%). Our family in the majority for each of these, even though there's naively only a 18% chance of that happening and they seem reasonably independent.

It's surprising to me that while parents mostly don't have the same names as each other (59%), only 11% of their kids have hyphenated names. I guess people realized that hyphenated names grow exponentially? I'd like to look at how the children's last names relate to parental gender, but that would involve annotating inferred genders for ~500 parents.

Boring details:

• There are 233 kids across six grades (K-5) with two classes per grade, for an average of 19 kids per class. Kindergarten is the biggest (45 kids, 22 and 23 each) while second grade is the smallest (30 kids, 15 and 15 each).

• 224/233 (96%) have two parents listed.

• Of the kids with two parents listed, 91/224 (41%) have the same last name as each other.

• 207/233 (89%) of kids have the same name as at least one of their parents.

• Of the 26 kids who have a different name, 15 (58%) are hyphenations, 7 (27%) have no obvious connection, 3 (12%) list only one parent and may share a last name with the other, and 1 (4%) is an unhyphenation (Sam Alpha-Bravo and Pat Charlie, with child Alex Bravo).

• 141 (76%) of families have one child in the school, 43 (23%) have two, and 2 (1%) have three.

• All parents are listed with email addresses, but 12/224 (5%) have the same email listed for both parents.

• 255/355 (72%) unique email address gmail accounts, 35 (10%) are yahoo, 13 (4%) are hotmail, 7% (2%) are aol, and 11 (3%) are edu.

• All but one parent is listed with a phone number, but 6/224 (3%) have the same phone listed for both parents.

• Of 357 unique phone numbers, 242 (68%) are Boston (including Somerville), 29 (8%) are NYC, 28 (8%) are Boston's inner suburbs, and 8 (2%) are the Bay Area. Boston's Northern suburbs (978 and 351) and Southern suburbs (508 and 774) are each below 1%, behind Chicago and Philly.