Lightning strikes, lasting less than a half-millionth of a second, often scorch the skin but don't cause internal burns. Just as crucial, most of the electricity in a lightning bolt does not pass through the body. Rather, it dissipates over the skin in what's known as a flashover. Vernon Cooray, a lightning scientist at Uppsala University in Sweden, explains the phenomenon by contrasting the ways a human body and a tree react when struck.
Human-computer interaction (HCI) is the study and planned design of human and computer activities. HCI uses productivity, safety and entertainment to support and fulfill human-computer activities and is applied to various types of computer systems, including air traffic control, nuclear processing, offices and computer gaming.
Human-computer interaction research often involves experiments with human participants to test one or more hypotheses. One of the most common statistical tools for hypothesis testing is the analysis of variance (ANOVA). The ANOVA result is reported as an F-statistic and its associated degrees of freedom and p-value. This research note does not explain the analysis of variance, or even the F-statistic itself.