The direction of a correlation is either positive or negative. In a negative correlation, the variables move in inverse, or opposite, directions. In other words, as one variable increases, the other variable decreases. For example, there is a negative correlation between self-esteem and depression. In other words, the higher your self-esteem, the lower your feelings of depression.
Excel Communications was founded in 1988 by Dallas entrepreneur Kenny Troutt as a long distance reseller in the US telecom sector at the birth of telecom deregulation.
Microsoft Excel was based on another program, the first spreadsheet, known as Visicalc. It was invented by two men called Bob Frankston and Dan Bricklin in 1978 and launched in 1979. There were a number of other spreadsheet programs around before Excel too, including one called Multiplan that Microsoft had created. Multiplan was launched in 1982 and Excel in 1985. The Microsoft Corporation was founded by Bill Gates.