Which of the following procedures is always equivalent to adding 5 given numbers and then dividing the sum by 5?
I. Multiplying the 5 numbers and then finding the 5th root of the product.
II. Adding the 5 numbers, doubling the sum, and then moving the decimal point one place to the left.
III. Ordering the 5 numbers numerically and then selecting the middle number.
(B) I only
(C) II only
(D) III only
(E) I and III
how to find the average of 5 numbers?