Iframe Tag just adds another window on your Webpage and due to which whenever a browser loads a page with an iframe it loads the original Page and Iframe as a separate 2 different pages. So in some cases Iframe is not-supported and thus, displays an Error.
Sigma is a Greek letter that corresponds somewhat to our letter S and thus sigma is often used to stand for some concept that starts with S. There is an upper case (capital) sigma and a lower case (small) sigma. They are and. is most ofter used to indicate a sum.
Six Sigma is simply a method of efficiently solving a problem. Using Six Sigma reduces the amount of defective products manufactured or services provided, resulting in increased revenue and greater customer satisfaction. Six Sigma identifies the cause(s) of your problem to efficiently develop effective solution(s).