Similar to a z score, t scores measure the relative location of a score within a distribution. The distribution of t scores is a standardized distribution which has a mean of 50 and standard deviation of 10.

The resources in this section focus exclusively on the t statistic and the statistical procedures for which it can be used.

  • t Scores & Procedures
  • SPSS Software Tutorials
  • Other Software
  • t Scores & Procedures
    • t Statistics: An Introduction
    • t Procedures: Inferences about the Population Mean
      t Procedures: Inferences about the Population Mean

      t Procedures are very similar to the z procedures and are used when the distribution of the data are not perfectly normal, and when the population standard deviation of a variable is unknown. The interpretation of t scores is similar to the interpretation of z scores. However, the t distribution has a slightly different shape. It is symmetric, but not normal. It has a single peak, and a mean of 0, which is the center of the distribution, but that tails are higher and fatter, and the distribution has more spread. Further, the t distribution looks different for different sample sizes. The following presentation describes the properties of the t distribution, and demonstrates how to use t scores to make inferences about a population mean and to compare matched samples. The software tutorials show how to conduct these procedures in SPSS.

      Diana Mindrila, Ph. D.
      Phoebe Balentyne, M.Ed.

      t Procedures: Inferences about the Population Mean

    • t Procedures: Comparing Independent Samples
      t Procedures: Comparing Independent Samples

      t procedures can be used to compare variables across two independent samples. For instance, researchers may want to know whether the average performance on a certain achievement test differs significantly between males and females. The following narrated presentation demonstrates how to estimate a confidence interval for the mean difference between two populations, and how to test whether this difference is statistically significant. The presentation also discusses of the assumptions that must be met, and the robustness of t procedures to the violation of these assumptions. The software tutorial demonstrates how to perform an independent samples t test using SPSS.

      Diana Mindrila, Ph. D.
      Phoebe Balentyne, M.Ed.

      t Procedures: Comparing Independent Samples

  • SPSS Software Tutorials
    • Confidence Interval for a Population Mean (SPSS)
      Confidence Interval for a Population Mean (SPSS)

    • One Sample t-Test (SPSS)
      One Sample t-Test (SPSS)

    • Independent Samples t-Test (SPSS)
      Independent Samples t-Test (SPSS)

    • Matched Pairs t-Test (SPSS)
      Matched Pairs t-Test (SPSS)

      The following presentation demonstrates how to conduct a matched pairs t test in SPSS.

    • SPSS Tutorial: Paired Samples t & Wolcoxon
      SPSS Tutorial: Paired Samples t & Wolcoxon

      The following presentation demonstrates how to conduct paired samples t and Wilcoxon Signed Ranks tests in SPSS.

      Download the SPSS Tutorial: Paired Samples t & Wilcoxon Signed Ranks Tests Handout [PDF]

  • Other Software