Type I and Type II errors — MCQs

A researcher is trying to determine whether a newly discovered substance X can be useful in promoting wound healing after surgery. She conducts this study by enrolling the next 100 patients that will be undergoing this surgery and separating them into 2 groups. She decides which patient will be in which group by using a random number generator. Subsequently, she prepares 1 set of syringes with the novel substance X and 1 set of syringes with a saline control. Both of these sets of syringes are unlabeled and the substances inside cannot be distinguished. She gives the surgeon performing the surgery 1 of the syringes and does not inform him nor the patient which syringe was used. After the study is complete, she analyzes all the data that was collected and performs statistical analysis. This study most likely provides which level of evidence for use of substance X?

You are reading through a recent article that reports significant decreases in all-cause mortality for patients with malignant melanoma following treatment with a novel biological infusion. Which of the following choices refers to the probability that a study will find a statistically significant difference when one truly does exist?

An 18-year-old male reports to his physician that he is having repeated episodes of a "racing heart beat". He believes these episodes are occurring completely at random. He is experiencing approximately 2 episodes each week, each lasting for only a few minutes. During the episodes he feels palpitations and shortness of breath, then nervous and uncomfortable, but these feelings resolve in a matter of minutes. He is otherwise well. Vital signs are as follows: T 98.8F, HR 60 bpm, BP 110/80 mmHg, RR 12. His resting EKG shows a short PR interval and a delta wave. What is the likely diagnosis?

A 55-year-old man with recurrent pneumonia comes to the physician for a follow-up examination one week after hospitalization for pneumonia. He feels well but still has a productive cough. He has smoked 1 pack of cigarettes daily for 5 years. His temperature is 36.9°C (98.4°F) and respirations are 20/min. Cardiopulmonary examination shows coarse crackles at the right lung base. Microscopic examination of a biopsy specimen of the right lower lung parenchyma shows proliferation of clustered, cuboidal, foamy-appearing cells. These cells are responsible for which of the following functions?

An 18-month-old girl is brought to the pediatrician’s office for failure to thrive and developmental delay. The patient’s mother says she has not started speaking and is just now starting to pull herself up to standing position. Furthermore, her movement appears to be restricted. Physical examination reveals coarse facial features and restricted joint mobility. Laboratory studies show increased plasma levels of several enzymes. Which of the following is the underlying biochemical defect in this patient?

A 40-year-old woman who works as a secretary presents to your office complaining of new pain and numbness in both of her hands. For the past few weeks, the sensation has occurred after long days of typing, but it now occasionally wakes her up from sleep. You do not note any deformities of her wrists or hands, but you are able to reproduce pain and numbness in the first three and a half digits by tapping the wrist. What is the best initial treatment for this patient's complaint?

A 63-year-old man with alpha-1-antitrypsin deficiency is brought to the emergency department 1 hour after his daughter found him unresponsive. Despite appropriate care, the patient dies. At autopsy, examination of the lungs shows enlargement of the airspaces in the respiratory bronchioles and alveoli. Enzymatic activity of which of the following cells is the most likely cause of these findings?

A 55-year-old woman presents with pain in both hands and wrists for several years. It is associated with morning stiffness that lasts for almost an hour. She has a blood pressure of 124/76 mm Hg, heart rate of 71/min, and respiratory rate of 14/min. Physical examination reveals tenderness and swelling in both hands and wrists. Laboratory investigations reveal the presence of anti-cyclic citrullinated peptide. Which of the following immune-mediated processes is responsible for this patient’s condition?

A 33-year-old man presents with yellowing of the eyes. He says symptoms onset acutely 3 days ago and have not improved. He says he has had similar episodes for the past 10 years. Each episode is self-limited, lasting no more than 3–5 days. The patient denies any recent history of nausea, weight loss, abdominal pain, light-colored stools, dark urine, or pruritus. Current medications are herbal supplements and a multivitamin. The patient is afebrile and vital signs are within normal limits. His BMI is 32 kg/m2. Physical exam is unremarkable. Laboratory findings are significant for the following: Total bilirubin 3 mg/dL Direct bilirubin 0.2 mg/dL AST/ALT/Alkaline phosphatase Normal Hematocrit/lactate dehydrogenase (LDH)/haptoglobin Normal Which of the following is the most likely diagnosis in this patient?

A 52-year-old man is seen by his endocrinologist for routine followup of his type 2 diabetes. Although he has previously been on a number of medication regimens, his A1C has remained significantly elevated. In order to try to better control his glucose level, the endocrinologist prescribes a new medication. He explains that this new medication works by blocking the ability of his kidneys to reabsorb glucose and therefore causes glucose wasting in the urine. Which of the following medications has this mechanism of action?