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.
A hypothesis is used in an experiment to define the relationship between two variables. The purpose of a hypothesis is to find the answer to a question. A formalized hypothesis will force us to think about what results we should look for in an experiment. The first variable is called the independent variable. This is the part of the experiment that can be changed and tested. The independent variable happens first and can be considered the cause of any changes in the outcome. The outcome is called the dependent variable.