Có 2 chuồng gà: chuồng I có 8 con mái, 4 con trống, chuồng II có 9 con mái, 3 con trống. a. Bắt ngẫu nhiên 3 con từ chuồng I. Hỏi trung bình có bao nhiêu con gà mái được bắt ra?
b. Bắt ngẫu nhiên 3 con từ chuồng II. Hỏi trung bình có bao nhiêu con gà mái được bắt ra?
c. Bắt ngẫu nhiên 3 con từ mỗi chuồng. Hỏi trung bình có bao nhiêu con gà mái được bắt ra?

The blue whale is the largest animal living on the earth. the average blue whale measures 100 feet long (30 meters) and weighs 300,000 pounds (136,000 kilograms). a whale’s head is 1⁄3 of the length of its body. a new baby whale is 1⁄4 the length of a grown whale. the average man is 1⁄17 the length of a blue whale, and 1⁄1,818 its weight. a human baby measures 1⁄4 of the length of an adult. calculate the following information: how long is a whale’s head? how long is a new baby whale? how tall is the average man? how much does the average man weigh? how tall is the average human baby?

In a survey of 1015 adults, a polling agency asked, "when you retire, do you think you will have enough money to live comfortably or not. of the 1015 surveyed, 534 stated that they were worried about having enough money to live comfortably in retirement. construct a 90% confidence interval for the proportion of adults who are worried about having enough money to live comfortably in retirement.

Given δjkl : δxyz, find x. a)10 b)12 c)16 d)20