Such volcanoes are devastating, but very rare. The last one happened at Toba in Sumatra, Indonesia, 74,000 years ago. The active volcanic system at Yellowstone National Park has resulted in super-eruptions-the most recent happened 640,000 years ago. Yellowstone's volcanism is powered by magma rising from a hotspot.
A biased opinion is based on a preconceived notion or idea about a thing, person or group of people based on personal beliefs. In psychology, a bias is known as a cognitive shortcut.. It is based on the idea that the human brain, in order to conserve energy, naturally looks for shorter paths to conclusions by using what has been ingrained to draw speedy conclusions.
Bias: A systematic error in the design, recruitment, data collection or analysis that results in a mistaken estimation of the true effect of the exposure and the outcome. Confounding: A situation in which the effect or association between an exposure and outcome is distorted by the presence of another variable. Positive confounding (when the observed association is biased away from the null) and negative confounding (when the observed association is biased toward the null) both occur. Confounder: an extraneous variable that wholly or partially accounts for the observed effect of a risk factor on disease status..