A survey has shown that public perceptions of comparative risks differ radically from the assessments of risk-management experts  For example, living near a nuclear power plant was judged a much greater risk by the survey respondents than it was by the experts  On the other hand, exposure to X-rays was judged a significantly lower risk by the survey respondents than it was by the experts  Psychologists have found that people tend to be more worried about risks they consider involuntary than about risks they consider voluntary
Thus the survey results were probably caused by the respondents' tendency to consider involuntary risks to be greater than they actually are
Not all of the survey respondents considered living near a nuclear power plant to be a voluntary risk.