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Question 1
Incorrect
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Choose the standard method for comparing distributions in data sets (such as between the expected frequency of an event and the observed frequency of an event) from the list of options.
Your Answer: Mean
Correct Answer: Chi squared (X²) test
Explanation:The Chi-squared test evaluates if two variables are related. The other statistical tests mentioned do not perform this function.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 2
Correct
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A study is carried out to assess the efficacy of a new anti-epileptic drug for children with absence seizures. The total number of the children selected for the study was 400, from which 150 children were assigned to take the new drug and 250 children were assigned in the control group. After a period of four months, only 15 children taking the new drug had a seizure compared to 100 children from the control group who had seizure. What is the correct value regarding the relative risk reduction?
Your Answer: 75%
Explanation:Relative risk reduction (RRR) tells you by how much the treatment reduced the risk of bad outcomes relative to the control group who did not have the treatment. In the previous example, the relative risk reduction of fever and rash in the group of the children on the intervention was 40 per cent (1 – 0.6 = 0.4 or 40 per cent). RRR = (EER -CER) / CER = (0.1 – 0.4) / 0.4 = -0.75 or 75% reduction.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 3
Correct
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In a study, 50 out of 100 smokers developed lung cancers and 50 out of 200 non-smokers developed lung cancers. Which of the following is accurate?
Your Answer: Relative risk=2
Explanation:Relative risk = (Incidence in exposed group)/incidence in unexposed group). So in this case RR = (50/100)/(50/200) = 2.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 4
Incorrect
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Which one of the following statements regarding the normal distribution is correct?
Your Answer: Standard deviation = mean / square root (variance)
Correct Answer: Mean = mode = median
Explanation:Normal distribution, also known as the Gaussian distribution, is a probability distribution that is symmetric about the mean. The normal distribution has the following properties:- It is symmetric around the mode, the median and the mean of the distribution.- It is unimodal- The area under the curve and over the x-axis is unity (i.e. equal to one).- Its density has two inflection points.- Its density is log-concave.The standard deviation (SD) is a measure of how much dispersion exists from the mean. SD = square root (variance)
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 5
Incorrect
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A study is carried out to assess the efficacy of a rapid urine screening test developed to detect Chlamydia. The total number of people involved in the study were 200. The study compared the new test to the already existing NAAT techniques. The new test was positive in 20 patients that were Chlamydia positive and in 3 patients that were Chlamydia negative. For 5 patients that were Chlamydia positive and 172 patients that were Chlamydia negative the test turned out to be negative. Choose the correct value regarding the negative predictive value of the new test:
Your Answer: 172/175
Correct Answer: 172/177
Explanation:The definition of negative predictive value is the probability that the individuals with truly negative screening test don’t have Chlamydia. The equation is the following: Negative predictive value = Truly negative/(truly negative + false negative) = 172 / (172 + 5) = 172 / 177
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 6
Correct
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There will be a proportion of people in a population who have the given condition, disease or attribute at a specified point in time or over a specified period of time. Which of following is the best term which can describe the above?
Your Answer: Prevalence
Explanation:Prevalence refers to the total number of cases of a particular disease or condition present in a population at a specific point in time or over a specified period. It provides a measure of how widespread the disease or condition is within the population.
Specificity and sensitivity are terms used to describe the accuracy of diagnostic tests.
Probability refers to the likelihood of an event occurring.
Incidence is a measure of how commonly or frequently a disease occurs in a specified population over a period by providing a quick measurement of new disease diagnoses.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 7
Incorrect
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A cohort study is developed to assess the correlation between blood pressure and working long hours. After 10 years of follow-up and for the 1050 individuals working less than 40 hours per week, 1000 patients had normal blood pressure and 50 patients were diagnosed with hypertension. For the 660 patients working more than 40 hours per week, 600 patients had normal blood pressure and 60 patients were diagnosed with hypertension. If you work more than 40 hours per week, what is the odds ratio of developing hypertension compared to the individuals working less than 40 hours per week?
Your Answer: 0.5
Correct Answer: 2
Explanation:An odds ratio (OR) is a measure of the association between an exposure and an outcome. The OR represents the odds that an outcome will occur given a particular exposure, compared to the odds of the outcome occurring in the absence of that exposure. Odds ratios are most commonly used in case-control studies, however they can also be used in cross-sectional and cohort study designs as well (with some modifications and/or assumptions). Wherea = Number of exposed casesb = Number of exposed non-casesc = Number of unexposed casesd = Number of unexposed non-casesOR=(a/c) / (b/d) = ad/bc
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 8
Incorrect
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A case-control study is developed to assess passive smoking as a risk factor for the development of asthma in children. The total number of patients recruited for this study is 200. 40 out of the 200 patients report at least one parent smoking in the house when they were younger. 200 more people without asthma are recruited and 20 out of them report that at least one parent smoked in the house when they were younger. What is the odds ratio of patients with asthma having been exposed to passive smoking during their childhood?
Your Answer: 4
Correct Answer: 2.25
Explanation:An odds ratio (OR) is a measure of association between an exposure and an outcome. The OR represents the odds that an outcome will occur given a particular exposure, compared to the odds of the outcome occurring in the absence of that exposure. Odds ratios are most commonly used in case-control studies, however they can also be used in cross-sectional and cohort study designs as well (with some modifications and/or assumptions). Wherea = Number of exposed casesb = Number of exposed non-casesc = Number of unexposed casesd = Number of unexposed non-casesOR=(a/c) / (b/d) = ad/bc
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 9
Correct
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There is a measure of dispersion of a set of data from its mean. Which of following is the best term which can describe the above?
Your Answer: Standard deviation (root mean square deviation)
Explanation:Standard deviation is defined as the measure of dispersion of a set of data from its mean. It measures the absolute variability of a distribution; the higher the dispersion or variability, the greater is the standard deviation and greater will be the magnitude of the deviation of the value from their mean.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 10
Correct
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What is the correct formula to calculate the positive predictive value?(TP = true positive; FP = false positive; TN = true negative; FN = false negative)
Your Answer: TP / (TP + FP)
Explanation:Positive predictive value is the probability that subjects with a positive screening test truly have the disease.Positive predictive value = true positive / ( true positive + false positive)
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This question is part of the following fields:
- Medicine
- Research Skills
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SESSION STATS - PERFORMANCE PER SPECIALTY
