SELECT MIN("Average") FROM table_78817 WHERE "Yards" > '167' AND "Team" = 'at tb' AND "Week" > '7'
Which Average has Yards larger than 167, and a Team of at tb, and a Week larger than 7?
CREATE TABLE table_78817 (
    "Week" real,
    "Team" text,
    "Carries" real,
    "Yards" real,
    "Average" real
)