The process of statistical study Flashcards
(26 cards)
Lis the 4 steps in conducting a statistical study
- Determine the design of the study
- state the question to be studied
- determine the population and variables
- determine the sampling method
- Collect the data
- Organize the data
- Analyze the data to answer the question
Identify the population of interest and the variable in this study.
“Neurologists want to study the effect of vitamin C on nerve disorders. The goal of the study is to see if taking an intravenous dose of vitamin C will reduce the amount of nerve pain reported by patients.
The population is ALL patients with nerve disorders.
Variables is the amount of vitamin C, amount of nerve pain.
An ____________ observes data that already exist.
observational study
An ________ generates data to help identify cause-and-effect relationships.
experiment
True or False
A statistician will refer to any ‘theoretical’ data collection as an experiment.
True
Which type of study would you conduct? (observational vs experiments)
‘You want to determine the average age of college students across the nation’
observational study
Which type of study would you conduct? (observational vs experiments)
‘Researchers wish to determine if flu shots actually help prevent severe cases of the flu’
experiement study
A ___________ sample has the same relevant characteristics as the population and does not favor one group from the population over another.
representative
How do you know if a sample is representative of the population?
???
‘My sample is all females in this class. Is it a representative sample?’
yes … keyword ALL
Cite five sampling techniques?
- simple random
- stratified
- cluster
- systematic
- !convenience
define simple random sample
every sample from the population has an equal chance of being selected.
define a stratified sample?
where the population is divided into subgroups called strata. The grouping variable is correlated with the measurement variable. A sample is drawn from each stratum.
Define cluster sampling?
The population is divided into subgroups, called clusters. The grouping variable is not correlated with the measurement variable. A sample can be drawn from at least one of the clusters.
Define systematic sampling?
selecting every nth member of the population
Define convenience sampling and the issues with using it?
the sample is convenient for the researcher to select, considered bias sampling.
Note: unethical
Identify the sampling method.
‘A pollster surveys 50 people in each of a senator’s 12 voting precincts’
simple sample
Identify the sampling method.
‘The quality control department at a cereal manufacturer measures the weight of every 10th box off of the assembly line.’
systematic sampling
Identify the sampling method.
‘A female student walks down the halls in her dorm asking students how much money they would spend in a food court in the dorm lobby in an effort to persuade the administration to offer such an opinion.’
convenience sampling (bias)
Identify the sampling method.
‘An educator chooses 5 of the school districts in the Chicago area and asks each household in those districts how many school-age children are in the home.’
cluster sampling
Identify the sampling method.
‘To determine who will win a $100,000 shopping spree at the mall, the manager draws a name out of a box of entires.’
simple random sampling
Q: What is the primary difference between cluster and stratified sampling?
???
Cite two observational studies?
cross-sectional
longitudinal
In a ______ study, data are collected at a single point in time.
cross-sectional (many members)
