Although several companies developed tablets throughout the 1990s and 2000s, the tablet computer only became mainstream after Apple introduced the iPad in 2010. Later that year, Samsung released the Galaxy Tab, the first tablet to run Google's Android operating system. Like the iPad, Android tablets can run millions of different apps, making tablets a portable option for both work and play.
A null hypothesis is one that is assumed to be true unless it has been contradicted. It is used to compare to another hypothesis. The experimental hypothesis is what you are observing, and you expect it to differ from the control. erm i know that a null hypothesis is when nothing happens at all i think.
It is an unfortunate circumstance that statistical methods used to test the null hypothesis are commonly called tests of statistical significance. The word significant misleads professional practitioners and the lay public into thinking that the research results are important for this reason.