statistics

Question

Write the null and alternative hypotheses for the following example. Determine if it is a case of a two-tailed, a left-tailed, or a right-tailed test.

To test whether the mean starting salary of college graduates is greater than 48,000 dollars per year.

Answer 1

 The hypotheses is what you think is happening. In this case it would be you think that people make more than $48,000 (H>$48,000) The null hypothesis is the negation of the alternate hypothesis. So the null hypothesis would be that people make $48,000 (null equal to $48,000).

 

Whether you use a one or two tail test depends on when your alternate hypothesis. Here, you think people make more than $48,000. Since you were indicating a direction it would be a one tail test to the right (more than $48,000). 

 

Next you would do a test of statistical significance. If the result is statistically significant, you can reject the null and infer the hypotheses. If it's not statistically significant, do not reject the null, and you are basically done.