Why were americans surprised by the tet offensive?

a. they had expected the offensive to take place months later.
b. the johnson administration had led them to believe that the enemy was not capable of launching a massive attack.
c. they had expected the offensive to take place months earlier.
d. the communists had promised not to launch an offensive.

For a science project, a high school research team conducted a survey of local air temperatures. based on the results of the survey, the found that the average temperatures were around 10 degrees higher than expected. this result was wrong. the trouble with the survey was that most of the locations were exposed to direct sunlight and located over asphalt or sand, which resulted in higher temperatures than normal. this is a classic example of an error in which phase of inferential statistics?