Mean and median: level

Research hypotheses that focus on the level of scores are usually best tested with the mean or another measure of central tendency such as the median value. For example, the hypothesis that media literacy is below a particular standard (e.g., 5.5 on a 10-point scale) among children refers to a level: the level of media literacy scores.

The hypothesis probably does not argue that all children have a media literacy score below 5.5. Instead, it means to say that the overall level is below this standard. The center of the distribution offers a good indication of the general score level.

For a numeric (interval or ratio measurement level) variable such as the 10-point scale in the example, the mean is a good measure of the distribution’s center. In this example, our statistical hypothesis would be that average media literacy score of all children in the population is (below) 5.5.

Testing one mean or median in SPSS

The one-sample t test in SPSS is explained in Figure 9.19.