Statistics - Hypothesis Testing Flashcards
What is a hypothesis?
A hypothesis is a statement made about the value of a population parameter. You can test a hypothesis about a population by carrying out an experiment or taking a sample from the population.
What is the test statistic?
The result of the experiment or the statistic that is calculated from the sample is called the test statistic.
In order to carry out a test, what are the two hypotheses you need to form?
- the null hypothesis, H0
- the alternative hypothesis, H1
What is the null hypothesis?
The hypothesis that you assume to be correct.
What is the alternative hypothesis?
Tells you about the parameter if your assumption is shown to be wrong.
What do you need to do in order to carry out a one-tailed hypothesis test?
- Formulate a model for the test statistic.
- Identify suitable null and alternative hypotheses.
- Calculate the probability of the test statistic taking the observed value (or higher/lower), assuming the null hypothesis is true.
- Compare this to the significance level.
- Write a conclusion in the context of the question.
Alternatively, you can find the critical region and see whether the observed value of the test statistic lies inside it.
What is a critical region?
A critical region is a region of the probability distribution which, if the test statistic falls within it, would cause you to reject the null hypothesis.
What is the critical value?
The first value to fall inside of the critical region.
What is the actual significance level?
The actual significance level of a hypothesis test is the probability of incorrectly rejecting the null hypothesis.
What do you need to do for a two-tailed test?
Halve the significance level at the end you are testing.
What is the difference between a one-tailed test and a two-tailed test?
A one-tailed test is used to test when it is claimed that the probability has either gone up or gone down. A two-tailed test is used when it is thought that the probability has changed in either direction.
