A new blood test is created to screen for breast cancer. Studies have revealed that it has a sensitivity of 75% for detecting clinically significant breast cancer and a specificity of 65%. What is the likelihood ratio for a positive test result?
A randomised controlled trial is conducted comparing a new medication or placebo for recovery from a certain illness.
What term best describes the probability of obtaining a result by chance at least as extreme as the one that was observed, assuming that the null hypothesis of no difference between the medication and placebo is true?
A small study examines the age of patients diagnosed with hypertension. A total of 64 patients were analyzed. The average age was 55 years, with a standard deviation of 8 years. What is the standard error of the mean?
A 28-year-old patient who is participating in a clinical trial comes to your clinic for a flu shot. He is uncertain if it is permitted while he is in the trial, so his trial coordinator is consulted. The coordinator explains that the patient is part of a study involving 150 participants to evaluate the effectiveness and adverse effects of a new allergy medication, and receiving the vaccine should not be an issue.
What phase of the clinical trial is the 28-year-old patient in?
A medical researcher wants to investigate the quality of life of patients with lung cancer, many years after their initial diagnosis. The researcher plans to identify patients who were diagnosed at least 10 years ago and administer a questionnaire to gather information about their quality of life since the diagnosis.
What potential bias could affect the results of this study?
A trial is conducted to evaluate the effectiveness of a new screening test for detecting heart disease in patients over the age of 50. The contingency table below shows the results for a group of patients who were tested:
Heart disease present Heart disease absent
Test positive 120 15
Test negative 10 255
What is the positive predictive value of the new screening test for detecting heart disease (rounded to 2 decimal places)?
A researcher wants to investigate dietary variations between patients aged 50-60 years with impaired glucose tolerance (HbA1c 42-47 mmol/mol) and those without impaired glucose tolerance (HbA1c <42 mmol/mol). The participants who agree to take part are requested to maintain a food journal for two weeks. The researcher is worried that the participants' eating habits during this observed period may deviate from their regular routine, impacting the accuracy of the study. What is the term used to describe this phenomenon?
A new type of blood test is being studied that may accurately detect the presence of a certain disease in elderly patients. One hundred and fifty patients who have the disease confirmed via the gold standard, a specific medical test, are recruited, along with one hundred and fifty patients who do not have the disease. They are all subjected to the new blood test and the results are as follows:
Disease present on medical test Disease absent on medical test
Blood test positive 90 30
Blood test negative 60 120
What is the positive predictive value?
A GP is concerned about the number of cases of hypertension he is seeing in his practice. He conducts a search of the practice records to investigate further. In the practice population of 15000 patients, he identifies 200 patients with a diagnosis of hypertension, with 20 of those diagnosed between 1st January 2021 and 31st December 2021. He also notes four deaths in the past year with hypertension named on part one of the death certificate.
What was the incidence of hypertension for the year 2021 in this GP practice?
A public health doctor is studying the occurrence and frequency of hypertension in the local region. In 2017, there were 100,000 people with hypertension in the area, and 1,500 new cases were reported that year. In 2018, there were 110,000 people with hypertension in the area, and 2,500 new cases were reported that year.
What conclusions can be drawn about the occurrence and frequency of hypertension in this region?