According to the disclosure, an inspection apparatus determines whether a defect has occurred in a plurality of first inspection objects by comparing a reference range with the measurement value of the plurality of first inspection objects, identifies a plurality of second inspection objects in which a first error has occurred, and a plurality of third inspection objects in which a second error has occurred based on a result of determination whether the defect has occurred, adjusts the reference range based on measurement values of the plurality of second and third inspection objects, determines at least one of an occurrence probability of the first error and the second error based on the adjusted reference range, and displays at least one of a graph indicating the result of determination whether the defect has occurred, the adjusted reference range, the determined occurrence probability of the first error and the second error.