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.