The sequential operations in scientific research are

Concept

Scientific research builds dependable explanation in stages. An observed association is only a starting point; alternative causes must be ruled out before a finding can be extended beyond the observed cases.

Generalisation then supports a broader statement, and theorisation integrates such general statements into an explanatory framework.

Application

Apply that dependency to the four operations named in the item:

1. Co-variation: first establish that two variables vary together; this supplies the empirical relation to be investigated.

2. Elimination of spurious relations: next test controls and alternative explanations so that the observed association is not merely produced by a third factor.

3. Generalisation: after the relationship survives those checks, extend the supported finding to the relevant class or population within the study's limits.

4. Theorisation: finally connect the generalised relationship with concepts and propositions that explain why the pattern occurs.

Cross-check

The order follows a dependency chain: a relationship must be observed before it can be tested for spuriousness; only a supported relationship can be generalised; theory is built from the resulting general statements. Therefore the sequence is Co-variation → Elimination of Spurious Relations → Generalisation → Theorisation.