#1
Which of the following is an example of a categorical variable?
Height in centimeters
Temperature in degrees Celsius
Gender (Male/Female)
Age in years
#2
Which type of sampling method involves selecting every kth individual from a list after a random start?
Simple random sampling
Stratified sampling
Systematic sampling
Cluster sampling
#3
What statistical measure is used to assess the strength and direction of a linear relationship between two continuous variables?
Odds ratio
Correlation coefficient
Relative risk
Chi-square statistic
#4
What type of study design is often used to investigate the prevalence of a health condition in a specific population at a single point in time?
Cohort study
Cross-sectional study
Case-control study
Experimental study
#5
In statistical hypothesis testing, what is the significance level typically set at to determine statistical significance?
#6
Which of the following is an example of a continuous variable?
Gender (Male/Female)
Blood type (A/B/AB/O)
Height in centimeters
Favorite color
#7
What is the purpose of randomization in experimental study designs?
To eliminate bias
To increase statistical power
To ensure generalizability
To control confounding variables
#8
In a crossover study design, participants receive different treatments at different time points. What is the primary advantage of this design?
Reduces the impact of carryover effects
Increases participant blinding
Enhances external validity
Minimizes selection bias
#9
In a clinical trial, what is the purpose of a placebo group?
To compare the effectiveness of two different treatments
To provide a baseline for comparison with the treatment group
To ensure blinding of participants and researchers
To increase the sample size
#10
What is the purpose of blinding in a research study?
To eliminate confounding variables
To prevent bias in the assessment of outcomes
To increase the external validity of the study
To control for selection bias
#11
In statistical terms, what does the p-value represent?
The probability of rejecting a true null hypothesis
The probability of accepting a false null hypothesis
The probability of obtaining the observed results by chance alone
The probability of a Type II error
#12
What is the purpose of stratification in epidemiological studies?
To control for confounding variables
To increase the precision of estimates within subgroups
To maximize external validity
To ensure blinding of participants
#13
What is the main difference between observational and experimental study designs?
Observational studies involve manipulation of variables, while experimental studies do not.
Experimental studies involve random assignment, while observational studies do not.
Observational studies rely on randomization, while experimental studies do not.
Experimental studies can establish causation, while observational studies cannot.
#14
When analyzing a cohort study, what does the hazard ratio represent?
Odds of an event in the exposed group compared to the unexposed group
Ratio of the means between two groups
Risk of an event in the exposed group compared to the unexposed group over time
Difference in proportions between two groups
#15
In a factorial experimental design, how many independent variables are manipulated simultaneously?
#16
What is the purpose of a confounding variable in a research study?
To strengthen the relationship between the independent and dependent variables
To control for extraneous variables
To introduce bias and obscure the true relationship
To enhance the internal validity of the study
#17
What is the primary advantage of using a cross-over design in clinical trials?
Reduces the impact of carryover effects
Increases participant blinding
Enhances external validity
Minimizes selection bias
#18
In statistical terms, what does the term 'power' refer to?
The probability of making a Type I error
The probability of making a Type II error
The ability of a study to detect a true effect when it exists
The precision of the study estimates