Final answer:
There are three types of medical errors described in the question: giving a patient an antibiotic without establishing the bacterial origin of the symptoms and signs, failing to prescribe the appropriate medication for a myocardial infarction candidate patient prior to discharge, and giving the wrong dose of medication to a patient.
Step-by-step explanation:
The first type of medical error described is giving a patient an antibiotic without establishing the bacterial origin of the symptoms and signs. This can lead to inappropriate treatment and potential harm to the patient. The second type is failing to prescribe the appropriate medication for a myocardial infarction candidate patient prior to discharge. This can result in a worsened outcome for the patient. Finally, the third type of medical error is giving the wrong dose of medication to a patient. This can lead to adverse effects or treatment ineffectiveness.