التجميع والمعدلات والمقامات

groups = [(1, 2), (9, 90)]
unweighted = sum(successes / total for successes, total in groups) / len(groups)
combined = sum(successes for successes, _ in groups) / sum(total for _, total in groups)
print(f"unweighted={unweighted:.2f} combined={combined:.2f}")

unweighted=0.30 combined=0.11

تعطي 0.30 كل فئة وزناً متساوياً، وتمثل 0.11 المعدل المقرب عبر 92 فرصة كلها. يختلف المقام والهدف، لا صحة الحساب فقط.

import sqlite3
from contextlib import closing

with closing(sqlite3.connect(":memory:")) as connection:
    connection.execute("CREATE TABLE measurements (team TEXT, value INTEGER)")
    connection.executemany("INSERT INTO measurements VALUES (?, ?)", [("A", 10), ("A", None), ("B", 0)])
    query = "SELECT team, COUNT(*), COUNT(value), AVG(value) FROM measurements GROUP BY team ORDER BY team"
    for team, rows, observed, average in connection.execute(query):
        print(f"{team} rows={rows} observed={observed} average={average:.1f}")

A rows=2 observed=1 average=10.0
B rows=1 observed=1 average=0.0

لدى A قياس صالح واحد من صفين، ولدى B قياس صفري حقيقي واحد. يكشف عرض عدد الصفوف والمعروف الفرق الذي يخفيه المتوسط وحده.