Inferential Statistics
Understanding Inferential Statistics
- Inferential statistics allow researchers to draw conclusions that extend beyond the immediate data.
- They help in making inferences about populations using data drawn from a sample.
- Unlike descriptive statistics, which simply describe data, inferential statistics test hypotheses and make predictions about future occurrences.
Key Statistical Tests
- The t-test is used when the data is interval or ratio level and the aim is to compare the means of two conditions or groups.
- Chi-square is useful when dealing with nominal or categorical data. It shows if there’s a significant association between two variables.
- Analysis of Variance (ANOVA) is used when comparing the means of more than two groups.
- A correlation test is used to assess the relationship between two variables.
Tests for Significance
- The Null Hypothesis states that there would be no effect or relationship in the population. It is the hypothesis that is tested for possible rejection.
- The Alternative Hypothesis states that there would be an effect or relationship.
- Inferential statistics provide a p-value, which indicates the probability that the results occurred by chance.
- A p-value of less than 0.05 is often considered significant. It suggests there’s less than a 5% chance that the data occurred by chance alone.
Making Inferences
- Inferential statistical tests give a direction to the conclusion, allowing researchers to accept or reject the null hypothesis.
- They allow for generalisation of results from a sample to a population.
- Keep in mind possible errors. A Type I error is rejecting the null hypothesis when it is true. A Type II error is failing to reject a false null hypothesis.
- However, remember that statistical significance does not imply practical significance. The results you get must have real-world meaning and application.