The following is a self assessment for Ch 1 that is meant for you to review, assess your own understanding, and prepare for the end of unit assessment. You may take the assessment as many times as you like up to the due date, best score will be recorded.
Which sampling method selects every k^{th} individual after a random start?
Surveying only volunteers on a website mainly causes which sampling bias?
Dividing the population by age and randomly sampling each group is called?
Randomly choosing entire classrooms to survey illustrates which sampling method?
Which scenario is an experiment rather than an observational study?
Why is random assignment crucial in experiments but not required in observational studies?
What main limitation keeps observational studies from proving causation?
In an experiment, the variable intentionally manipulated by researchers is called the _____
Which study design best controls for confounding variables when testing a treatment?
A medical trial randomly assigns patients to a drug or placebo; what type of study is this?
When participants select their own treatment, the investigation should be labeled _____
Matching subjects on age and gender seeks to reduce which issue in observational studies?
Blinding procedures in experiments are primarily intended to reduce which kind of bias?
Researchers track sugar intake and weight without intervening; this is what kind of study?
Researchers follow 5,000 nonsmokers for 15 years, recording who starts smoking. Which study type is used?
Scientists compare 200 lung cancer patients with 200 healthy subjects to look back at past pollution exposure. Identify the study.
A survey measures blood pressure of city residents on one specific day to estimate hypertension prevalence. What type of study is this?
Tracking identical twins yearly from birth to age 30 to see weight divergence exemplifies which observational design?
Investigators first select people with rare liver disease and similar disease-free controls, then assess past alcohol use. Study type?
Researchers analyze 2001–2020 hospital charts to link stress and ulcers. What study type is this?
Scientists follow 500 infants until adulthood recording yearly sleep habits. Which design describes this?
Which sampling method divides the population into groups, then randomly samples within each group?
A survey takes the first 30 students entering the cafeteria. What bias is introduced?
Which statement characterizes cluster sampling?
A sample omits rural residents because phone numbers list only cities. This is what bias?
An online magazine asks readers to click and vote on taxes. Which sampling issue arises?