Final answer:
A) Halve it
In a hypothesis test for a positive relationship that is two-tailed, you should halve the p-value if the initial p-value is calculated for a two-tailed test and you need it for a one-tailed test.
Step-by-step explanation:
When conducting a hypothesis test that you believe shows a positive relationship and is two-tailed, you should halve the p-value of the t-test if the p-value provided by a software like Excel is always for a two-tailed test. This adjustment is necessary because a two-tailed test checks for the possibility of a relationship in both directions, whereas a one-tailed test only checks in one direction. If you have a two-tailed p-value from software and you're only interested in a one-tailed test (positive relationship), you would halve the p-value to get the correct p-value for your one-tailed test.
To summarize the process:
- State the null hypothesis and the alternative hypothesis (Ha).
- Define the random variable.
- Calculate the test statistic.
- Calculate the p-value.
- Make a decision at your chosen significance level (e.g., 5%) about the null hypothesis.
- Understand Type I and Type II errors.