Hi. I am confused whether alpha could be used for refusal of null or alternative hypothesis? I’m stuck with this part and can’t proceed further with my research
Other factors that influence power that is more directly controllable than the size of treatment effect are:
The chosen alpha level. Smaller levels produce smaller values for power.
Whether a one-tailed or two-tailed test is used. Statistical power is greater for one-tailed tests
Sample size: Larger samples provide greater power
The goal of hypothesis testing is usually to reject the null hypothesis correctly, or in other words, to show that the treatment applied has affected. The probability of rightly rejecting the null hypothesis is called the power of a statistical test.
Power is calculated as 1 – α, where α is the probability of making a Type II error.
We set up contending hypotheses, choose a random sample from the population of concern and compute summary statistics. We then decide whether the sample data support the null or alternative hypotheses. The procedure can be broken down into the following five steps.
Step 1. Set up hypotheses and select the level of significance α.
Step 2. Select the appropriate test statistic.
Step 3. Set up a decision rule.
Step 4. Compute the test statistic.
Step 5. Conclusion.