Vocab Flashcards
what are descriptive statistics ?
they summarize data & describe information
what are inferential statistics ?
allow us to make inferences (estimates about smth data does not tell us) = use sample
what’s a variable ?
measure that takes on different values
what are the 2 big types of variables ? 2 sub types?
Numerical/quantitative variable (continuous or discrete) Categorical variables (nominal or ordinal)
what is a cross sectional data set ?
observing different entities at same point in time
what is a time series/ longitudinal data set ?
entity is observed at more than one point in time
how do you call the object described by a dataset?
Individual
what is the difference between an experiment and an observational study?
experiment = imposes treatment on individual to observe their reaction
Observational study = does not intervene, aim is to describe
What is called the population in a study?
entire group of individual about which we want info
What is the difference between a sample study and a census ?
Sample study = uses part of the population from which they collect data to draw conclusion
Census = attempts to include entire population in survey
When is a sample biased? what kind of biases exist?
- When the sampling systematically favors a certain outcome
- convenience sampling (itwier chooses who to sample)
- voluntary response sampling
what is a Simple Random Sample ?
SRS size of n individuals is when the ppl are chosen in such a way that any set of n individuals have the same chance to be in the sample selcted
