Which of the following represents the most accurate estimation of 4 + 8?

If 20% of a number is 35, what is 50% of that number?

The graph represents the gallons of water in a water tank with respect to the number of hours since it was completely filled

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?