Biostatistics: Introduction to Biostatistics (B300) - Practice Flashcards

15 practice flashcards covering key concepts from the lecture notes. Q&A style.

What is the difference between observational studies and experiments, in terms of data and causality?

Observational studies observe data without manipulation and cannot prove causality; experiments randomly assign treatments, allowing causal conclusions.

In biostatistics, what do 'population' and 'sample' refer to, and when can results be generalized?

Population is the entire group of interest; sample is a subset studied; results generalize to the population when the sample is randomly drawn.

What is a census, and what are common challenges associated with it?

A census attempts to include everyone in the population; challenges include high cost, nonresponse, and changing populations (e.g., immigrants, births, deaths).

Name the four main types of variables discussed in the notes.

Numerical continuous, numerical discrete, categorical nominal, and categorical ordinal.

Give examples of discrete numerical variables.

Counting quantities such as number of children, number of classes taken, or cars owned.

Give examples of continuous numerical variables.

Measured quantities such as height, weight, or age when measured with precision.

How is a proportion defined and how do you convert it to a percentage?

Proportion is the ratio of a subset to the total; percentage is that proportion multiplied by 100%.

What is anecdotal evidence, and why is it limited?

Evidence based on personal stories or isolated cases that may not be representative of the population.

What is a 'cheat sheet' and how is it used in this course's exams?

An eight and a half by eleven page, two-sided sheet of notes allowed for exams; not open-book; used to summarize notes.

In the chronic fatigue syndrome case study, what were the treatment and control conditions and how many participants were in each group after dropout?

Treatment: cognitive behavioral therapy; Control: relaxation; post-dropout, 27 in treatment and 26 in control (19/27 and 5/26 with good results).

Using the hours of study and GPA example, which variable is explanatory (independent) and which is the response (dependent)?

Hours of study is the explanatory (independent) variable; GPA is the response (dependent) variable.

What is a scatter plot used to illustrate in data analysis?

A scatter plot shows the relationship between two numerical variables and helps identify possible associations and outliers.

What role does random sampling play in generalizability of study results?

If data are randomly sampled, the results can be generalized to the population; without random sampling, generalizability is limited.