Question

Whenever you conduct a hypothesis test when you believe there is a positive relationship (2-tailed), make sure to do what with the p value of the t test? (P-value of excel always 2-tailed)

A) Halve it
B) Double it
C) Square it
D) Take the square root

Answer 1

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:

1. State the null hypothesis and the alternative hypothesis (Ha).
2. Define the random variable.
3. Calculate the test statistic.
4. Calculate the p-value.
5. Make a decision at your chosen significance level (e.g., 5%) about the null hypothesis.
6. Understand Type I and Type II errors.