Scientists use relevant principles, and under the condition that other conditions remain the same, according to the more severe the development of myocardial infarction, the fact that the calcium content in hair decreases correspondingly, that is, the reduction of calcium content in hair and the heart muscle There is a quantitative covariant relationship between the development of infarct conditions, and it is concluded that the analysis of the calcium content in hair can predict the development of myocardial infarction conditions. Was this conclusion used? ['deductive reasoning.', 'inductive reasoning.', 'analogical reasoning.', 'Logical method for causality.']