Contents
- 1 What happens if the null hypothesis is rejected when it is false?
- 2 Is power the probability of rejecting a false null hypothesis?
- 3 What is the error that can occur if we reject Ho?
- 4 When to reject or reject the null hypothesis?
- 5 What happens when p value is less than significance?
- 6 How big is the probability of finding a null hypothesis?
What happens if the null hypothesis is rejected when it is false?
When we fail to reject the null hypothesis when the null hypothesis is false. The “reality”, or truth, about the null hypothesis is unknown and therefore we do not know if we have made the correct decision or if we committed an error.
Is power the probability of rejecting a false null hypothesis?
Power is the probability of rejecting the null hypothesis when, in fact, it is false. Power is the probability of making a correct decision (to reject the null hypothesis) when the null hypothesis is false. Power is the probability that a test of significance will pick up on an effect that is present.
What type of error is made if you fail to reject the null hypothesis when the null hypothesis is actually false?
A type I error (false-positive) occurs if an investigator rejects a null hypothesis that is actually true in the population; a type II error (false-negative) occurs if the investigator fails to reject a null hypothesis that is actually false in the population.
What is the error that can occur if we reject Ho?
A TYPE I Error occurs when we Reject Ho when, in fact, Ho is True. In this case, we mistakenly reject a true null hypothesis. A TYPE II Error occurs when we fail to Reject Ho when, in fact, Ho is False.
When to reject or reject the null hypothesis?
Let’s return finally to the question of whether we reject or fail to reject the null hypothesis. If our statistical analysis shows that the significance level is below the cut-off value we have set (e.g., either 0.05 or 0.01), we reject the null hypothesis and accept the alternative hypothesis.
Can a hypothesis be rejected at the significance level?
Alternatively, if the significance level is above the cut-off value, we fail to reject the null hypothesis and cannot accept the alternative hypothesis. You should note that you cannot accept the null hypothesis, but only find evidence against it.
What happens when p value is less than significance?
When your p-value is less than or equal to your significance level, you reject the null hypothesis. The data favors the alternative hypothesis. Congratulations! Your results are statistically significant. When your p-value is greater than your significance level, you fail to reject the null hypothesis. Your results are not significant.
How big is the probability of finding a null hypothesis?
This means that there is a 3% chance of finding a difference as large as (or larger than) the one in your study given that the null hypothesis is true. However, you want to know whether this is “statistically significant”.