Final answer:
The provided information does not directly answer the proportion of patients unable to state their medication's purpose. It instead focuses on statistical data regarding medication efficacy and patient beliefs about cure rates.
Step-by-step explanation:
The proportion of patients unable to state the purpose of the medication prescribed to them is not explicitly provided in the information given. Instead, the details discuss statistical tests related to the efficacy of two types of medications and errors in patient beliefs regarding cure rates. For instance, when comparing Medication A and Medication B, we assess the difference in proportions of patients not reacting after 30 minutes. If we want to investigate the understanding patients have of their medications, we would need a different set of data, ideally from a survey or study that asks patients to articulate the purpose of their prescriptions.