STAT 121 Test Study Questions Verified Answers
quantitative variable
numerical value that represents measurement (can you find the avg? YES!)
categorical variable
categorize/label values, place individual into one of several groups (can you find the avg? NO!)
parameter
numerical fact about the Population
statistic
numerical fact about the Sample
distribution vs relationship
one varb at a time vs two varb at a time
distribution
what values a varb can take on and how often those values occur
sampling
choosing individuals from the population to collect data from
population
ALL individuals in the ENTIRE group that is the target of our interest
"biased" if...
produces data that is not representative of the population
sampling frame
list of potential individuals to be sampled
, non-probability (bad) sampling techniques:
- quota sample
- volunteer sample
- convenience sample
- systematic sample
probability (good) sampling techniques:
- simple random sample (SRS)
- stratified sample
- multistage sample
- cluster sample
quota sampling
comparing different groups without randomization (ex: choose certain males and certain
females to participate)
volunteer sample
individuals select themselves to be included (ex: posting a survey link online, whoever wants to
can click on it)
convenience sample
individuals who participate were in the right place/time to suit the schedule of the researchers
(ex: ask everyone who walks out of the HFAC from 11-1)
systematic sample
choosing every Nth name on the list
probability sampling
any sampling technique that relies on random selection; each individual has a KNOWN chance
of being selected (people don't have to have the same chance of being selected); "good"
quantitative variable
numerical value that represents measurement (can you find the avg? YES!)
categorical variable
categorize/label values, place individual into one of several groups (can you find the avg? NO!)
parameter
numerical fact about the Population
statistic
numerical fact about the Sample
distribution vs relationship
one varb at a time vs two varb at a time
distribution
what values a varb can take on and how often those values occur
sampling
choosing individuals from the population to collect data from
population
ALL individuals in the ENTIRE group that is the target of our interest
"biased" if...
produces data that is not representative of the population
sampling frame
list of potential individuals to be sampled
, non-probability (bad) sampling techniques:
- quota sample
- volunteer sample
- convenience sample
- systematic sample
probability (good) sampling techniques:
- simple random sample (SRS)
- stratified sample
- multistage sample
- cluster sample
quota sampling
comparing different groups without randomization (ex: choose certain males and certain
females to participate)
volunteer sample
individuals select themselves to be included (ex: posting a survey link online, whoever wants to
can click on it)
convenience sample
individuals who participate were in the right place/time to suit the schedule of the researchers
(ex: ask everyone who walks out of the HFAC from 11-1)
systematic sample
choosing every Nth name on the list
probability sampling
any sampling technique that relies on random selection; each individual has a KNOWN chance
of being selected (people don't have to have the same chance of being selected); "good"
