Every twenty-fifth person who ordered a subscription to a weekly news magazine was contacted by market researchers to complete a survey of opinions regarding the magazine's contents. The researchers were most clearly employing a technique known as

The answer is random sampling.

Explanation:

Random sampling is a technique that involves selecting random, unrelated participants to carry out observations. The results can then be generalised to larger groups.

The greatest advantage of random sampling is that it's unbiased. However, it's possible that the participants do not accurately represent the larger population.

answer; the confederacy could afford to move a large number of prisoners hundreds of miles but could not afford to fee and house the prisoners;

local max is .5

step-by-step explanation:

the local maximum is for x values between 2 and 4

it looks like the x value is 2.5 and the y value is .5