Biostatistics Flashcards
A clinical trial can best be defined as a
(a) retrospective study examining the natural history of a disease process.
(b) prospective study that is randomized and double-blinded.
(c) retrospective study with subjects selected on the basis of presence or absence of an
illness.
(d) prospective study comparing the effect of an intervention with a control.
Answer: D
Commentary:A clinical trial can best be defined as a prospective study comparing the effect and
value of an intervention with a control. A study measuring the natural history of a disease
process is more observational in nature and can be either prospective or retrospective. Clinical
trials are not necessarily randomized or double-blinded. Clinical trials are prospective and not
retrospective in nature
2009
Informed consent documents for participation in research protocols must include language stating
(a) that confidentiality cannot be assured.
(b) that once the document is signed, participation will be required.
(c) the procedures to be used in the study.
(d) that the results of the study will be shared with the subject.
Answer: C
Commentary:Informed consent documents for participation in research protocols must include
the procedures to be used in the study. Informed consent documents must also assure
confidentiality of the subjects and outcomes of individuals participating in the research. Informed
consent documents must also state that subjects have the right to terminate involvement in the
study at any time, even after they have signed the consent document. It must also state that the
decision to terminate involvement in the study will not affect the individual’s ongoing medical
care. Informed consent documents do not provide information that research results will be shared
with the individual subjects
2009
A research study is performed to assess the degree of spasticity experienced by individuals after
traumatic brain injury. Spasticity in the gastrocnemius muscle is evaluated in 10 patients using
the Modified Ashworth Scale (0–5 scale). Which descriptive statistic is appropriate for
summarizing the ordinal data measured with this scale?
(a) Ratio
(b) Median
(c) Correlation
(d) Mean
Answer: B
Commentary:The appropriate descriptive statistical method used to summarize ordinal data such
as the values used in the Modified Ashworth Scale is the median. The median value is defined as the value that occurs in the middle of a set of values. The mean would be used to summarize ratio or interval type of data. The other options listed are not descriptive statistical measures.
2009
Which attribute is a characteristic of an experimental research design?
(a) Results primarily provide information on associations between variables.
(b) Manipulation of experimental variables is controlled.
(c) It is retrospective in nature.
(d) It is an observation of the natural history of a disease process.
Answer: B
Commentary:Experimental research designs enable investigators to determine a cause and effect
relationship between 2 variables; whereas, non-experimental research designs can only establish
an association between 2 variables. In an experimental research design an intervention or
experimental variable is manipulated and its effect on other variables is measured. Experimental
designs are prospective in nature. Cohort studies, in which researchers observe the natural history
of a disease process, are non-experimental.
2009
The validity of a functional outcome measurement tool is defined as the ability
(a) of two different raters to obtain the same conclusion.
(b) of the tool to measure what it is designed to measure.
(c) to minimize random error.
(d) to measure several different outcomes simultaneously
Answer: B
Commentary:The validity of a functional outcome measurement tool is defined as the ability of
the tool to measure what it is designed to measure. The ability to measure different outcomes
simultaneously does not impact the validity of the instrument, but the validity of the tool would
need to be established for each of the outcomes being measured. The ability of two different
raters to obtain the same conclusion is referred to as inter-rater reliability. Freedom from random
error is also related to the reliability of the instrument
2009
Informed consent requires that risks associated with participation in a study be described in terms of
(a) type, severity, and probability.
(b) probability alone.
(c) physical, but not psychological, risks.
(d) major, but not minor, risks.
(a)
Informed consent for participation in a research study requires that the risks be described in terms of type, severity, and probability. It is important to describe risks in each of these areas in order to fully inform the patient of the potential risks associated with study participation.
Relevant to investigational studies, the principle of justice requires that
(a) harm be minimized and benefits maximized.
(b) informed consent includes full disclosure of risks and benefits.
(c) research subjects be treated fairly and selected equitably.
(d) investigators respect the privacy of research subjects.
(c) The principle of justice requires subjects to be treated fairly and selected equitably. The principle of
beneficence ensures that researchers minimize harm and maximize benefits associated with research
involvement. The principle of autonomy ensures that informed consent includes full disclosure of risks
and benefits and that the privacy of subjects is respected
2008
Type 1 (alpha) error is best described as occurring in research when
(a) the study finds a positive benefit from the intervention, but no benefit really exists.
(b) the study finds no benefit from the intervention, but a benefit really exists.
(c) study results are biased by subject selection criteria.
(d) study results are not generalizable outside the research setting.
(a) Type 1 (alpha) error is best described as occurring in research when the study finds a positive benefit
from the intervention, but no benefit really exists. In this case, the study conclusions would be falsely
positive
2008
You are conducting a research study, and you want to use Functional Independence Measure (FIM)
scores as 1 of your outcome measures. Because FIM information is scored on a 1 to 7 scale to
describe the level of assistance an individual requires to perform a functional task, these scores
represent which category of research data?
(a) Nominal
(b) Ordinal
(c) Ratio
(d) Interval
B
FIM scores would be classified as ordinal data, bc in an ordinal scale, consecutive values are rank ordered, but not equally spaced. For example, although there is an order to the ranking in the FIM scale, the difference between a 2 and a 3 may not be equal to the difference between a 6 and a 7. Nominal data refers to data with discrete values (yes/no; alive/dead). With interval data, there are equal intervals between consecutive values. An example of interval data is temperature in degrees Fahrenheit. Ratio data are interval data with equal intervals between consecutive values, but with an absolute zero point.
2008
The benefits of quality outcomes management include
(a) providing guidance for alignment of the program with the needs of the patient.
(b) improved insurance reimbursement from third party payors.
(c) improved retention of staff.
(d) reduced expenses independent of outcomes.
(a) The primary benefit of quality outcomes management is that it provides guidance for aligning the
program with the needs of the patient. None of the other options are benefits of quality outcomes
management.
2008
. In 2003, which diagnosis-related group (DRG) had the most admissions to inpatient rehabilitation
facilities?
(a) Stroke
(b) Unilateral joint replacement in a lower extremity
(c) Amputation for circulatory disorders except upper limb and toe
(d) Hip or pelvis fracture
(b) In fiscal year 2003, the number of admissions to an inpatient rehabilitation facility with the diagnosis
related group unilateral joint replacement in a lower extremity was 124,754, stroke was 54,433,
amputation for circulatory disorders except upper limb and toe was 7,200, and hip or pelvis fracture was
5,863.
2008
Which statement describes an advantage of a single-subject research design (that is, A-B-A or multiple baseline design)?
(a) It can account for variability between subjects.
(b) It permits medication trials with no washout period.
(c) It can establish cause and effect relationships.
(d) It is useful for interventions with prolonged or extended effects.
(c) An advantage of a single-subject research design (A-B-A design) is that this design can establish cause and effect relationships similar to other true experimental designs. Single subject research designs involve systematic, repeated measurement of a dependent variable over time through 1 or more baseline and intervention phases. The primary limitation with a single-subject research design is that it only establishes the cause and effect relationship for the subject involved in the study. Therefore, these results cannot be assumed to occur in others, because of the variability between subjects. Typically, a single subject research design requires a washout period between medication trials to ensure that the effects of the medication are no longer active. Single subject research designs are especially useful for interventions that do not have extended or prolonged effects. If the intervention has only short-term effects, then a difference in the outcome measured can be clearly demonstrated by comparing results when the intervention is in use against results obtained when it has been removed.
2007
Your co-resident presents an article in journal club on a new medication and its impact on outcomes following traumatic brain injury. On which point would you NOT need assurance before you decide to use this medication in your clinical practice?
(a) That the research study results are clinically significant
(b) That bias was eliminated from the study
(c) That the research study results are statistically significant
(d) That research investigators used valid outcome measures
(b) When critically evaluating the medical literature, it is important to consider if the results of the study are both clinically and statistically significant. It is also important to consider whether the outcome assessment tools have been validated for both accuracy and reliability. While biases that may impact the outcome of the study also must be considered, it is often impossible to completely eliminate bias from the study.
2007
Which statement accurately characterizes a meta-analysis?
(a) It summarizes the results of randomized controlled trials.
(b) It summarizes the findings of an expert panel.
(c) It groups research on a particular topic area into 3 tiers.
(d) It summarizes findings of a single research protocol that is carried out a multiple centers.
(a) A meta-analysis summarizes the results of randomized controlled trials on a particular topic or research question. A consensus statement summarizes the findings of an expert panel. In developing a consensus statement and reviewing the literature, research studies are typically divided into 3 tiers based on the type of research performed. A multi-center study implements a particular research protocol at multiple centers at different institutions
2007
An exclusion criterion for resistance training in patients with stable cardiac disease is
(a) peak exercise capacity at 7 metabolic equivalents (METs).
(b) prior history of a stroke.
(c) controlled hypertension.
(d) severe valvular disease
(d) Exclusion criteria for resistance training in stable cardiac patients include congestive heart failure, severe valvular disease, poor left ventricular function, uncontrolled dysrhythmias, and peak exercise capacity under 5 METs
2007
