30.4 The test statistic: Two independent means
The observed sample mean difference (observations), relative to what was expected, is found by computing the test statistic, in this case, a t-score. The software output (jamovi: Fig. 30.1; SPSS: Fig. 30.2) can be used, but the t-score can also be computed manually:
t=sample statistic−assumed population parameter, from H0standard error for sample statistic=(ˉxP−ˉxC)−(μP−μC)s.e.(ˉxP−ˉxC)=51.594−019.612=2.631, as in the software output.