Shortly before the 1932 presidential election, a national magazine conducted a telephone survey of voters. Based on the results of the survey, the magazine predicted that Herbert Hoover (Republican) would beat Franklin Roosevelt (Democrat) by a landslide. In fact, exactly the opposite happened. The trouble with the survey was that in the Depression era, only the rich could afford phones. Plus, wealthy people were more likely to vote Republican than Democrat. This is a classic example of an error in which phase of inferential statistics?

a. data gathering
b. data organisation
c. probability-based inference
d. data analysis

Data gathering is a way of collecting information, where information is gathered in a systematic way and the surveyed persons are asked questions related to the research. Then the results are studied and an outcome is estimated. Here, only a few percent of the total population were asked about the research. A major voting population were not even considered here. Hence, it was a fault in gathering data.