The null hypothesis[math]H_0[/math] is a claim about the value of a population parameter. The alternate hypothesis[math]H_1[/math] is a claim opposite to [math]H_0[/math].
A test of hypothesis is a method for using sample data to decide whether to reject [math]H_0[/math]. [math]H_0[/math] will be assumed to be true until the sample evidence suggest otherwise.
A test statistic is a function of the sample data on which the decision is to be based.
A rejection region is the set of all values of a test statistic for which [math]H_0[/math] is rejected.
Type I error: you reject [math]H_0[/math] when [math]H_0[/math] is true. [math]P(\text{Type I error}) = P (reject H0[/math]. The resulting α is called the significance level of the test and the corresponding test is called a level α test. We will use test procedures that give α less than a specified level (0.05 or 0.01).
