Let's say, I have an intelligence test made of 60 questions (items) which produces results for two intelligence constructs on a 0-100 scale (for instance crystallised and fluid intelligence).
I only have respondent's final scores on the two constructs. So, I don't have answers to single items. In such a scenario, I cannot calculate Cronbach's Alpha as a measure of internal consistency, because I don't have single items' scores.
Is there any reliable alternative measure of reliability that I could use, only having final test scores?