In the author's opinion, in 1936, Gallup and Roper ................. .

In the history of public opinion research, no poll has ever
gained so much notoriety as that conducted in 1936 fay
Literary Digest magazine. More than 10 million ballots
were sent to readers to get their preferences in the
upcoming presidential election between Franklin
Roosevelt and Alfred Landon. The returns indicated that
Landon would win easily. This poll was contradicted by
separate statistical samplings taken by Gallup and Roper,
which pointed to a Roosevelt victory. Roosevelt won in
the first great landslide, that is, overwhelming victory,
election of the 20th century. The problem was in the
method of polling. The Digest poll was a kind of survey
called a straw poll, which was completely nonscientific.
The Gallup and Roper polls, by contrast, were more
recently devised and were carefully calculated statistical
samplings.