34.2 Using software
Software is used to compute the value of . For the red deer data (Fig. 33.2), the relationship is approximately linear, and the jamovi output (Fig. 34.5) and SPSS output (Fig. 34.6) show that :
- Direction: The sign of indicates the direction. Here we see a negative relationship: Higher ages are associated with lighter molars (in general), which makes sense.
- Variation: The value of indicates the strength of the relationship. Here, perhaps we could describe the variation as moderate.

FIGURE 34.5: jamovi correlation output for the red deer data

FIGURE 34.6: SPSS correlation output for the red deer data