Data Types
What type of data would marital status be?
Nominal; no natural order
Instead of using actual names, subjects included in the National Health and Nutrition Examination Survey are coded with consecutive numbers.
Which level of measurement is most appropriate?
Nominal; the numbers have no intrinsic order
What are the outcome and exposure?:
A study in California among 18-24-year-olds compared smoking to an increased risk of lung cancer.
exposure = smoking
outcome = lung cancer
The investigator measures fish intake at baseline and periodically examines subjects at follow-up visits to see if those who eat more fish have fewer CHD events
Case-control
Cohort
Cross-sectional
Experimental
(observational) cohort
A group followed over time
refers to the situation when each person in the population has an equal chance (probability) of
being selected in the sample; and the selection of each person is independent of the selection of any other person.
Simple random sample
What type of data would letter grades be?
Ordinal; natural order
A research study on the effectiveness of PPE includes a likert scale of perceived safety. What level of measurement would this describe?
Ordinal data
What are the outcome and exposure?:
A study was done in 1986 investigating the rates of liver cancer between males who did and did not consume aflatoxin.
exposure = aflatoxin
outcome = liver cancer
Subjects are interviewed about current and past history of fish intake and correlates results with history of CHD and current coronary calcium score
(observational) cross sectional
A group examined at one point in time
numbers that describe the population
Parameter
What type of data would the number of headaches in a week be?
Discrete; it is countable
you can't have half of a headache
What type of data would socioeconomic status be?
Ordinal
What are the outcome and exposure?:
A study in Nebraska comparing the consumption of caffeine during pregnancy to low birth weight
exposure = caffeine during pregnancy
outcome = lbw
An interviewer examines a group of patients with CHD (cases) and compares them with a group who did not have CHD (controls), asking about past fish intake
(observational) case-control
two groups selected based on the presence or absence of an outcome
a number that can be computed from a sample
Statistic
What type of data would Blood alcohol concentration be?
Continuous data; it is measurable
What type of data would the number of subjects in a driving study be?
Discrete
What are the outcome and exposure?:
A study in Illinois compared low birth rates in children under 1-year-old to the likelihood of having hypertension later in life.
exposure = lbw
outcome = hypertension
A researcher randomly assigns subjects to receive fish oil supplements or a placebo, then follows both treatment groups for several years to observe the incidence of CHD
(Experimental) randomized controlled trial
two groups created by a random process, and a blinded intervention
To make generalizations about the entire population based on studying the sample
inference
What type of data would cancer stages be?
Ordinal; stage 1, stage 2, stage 3...
What type of data would the exact times that a randomly selected driver spends texting while driving during the past 7 days be?
Continuous
What are the outcome and exposure?:
Samples of subjects with and without heart disease were selected, then researchers looked back in time to determine whether they took aspirin on a regular basis.
exposure = aspirin consumption
outcome = heart disease
Contruct a sample without consideration of disease or exposure and measure disease and exposure at the same time
cross-sectional
A subset of the population
sample