Chapter 1 Flashcards
All the individual units of interest based on your question
Population
A subset of the population that you are actually testing, representative of the entire population
Sample
the study of methods to describe and measure aspects of nature from samples, all about estimation
Statistics
testable statement regarding a parameter
Statistical Hypothesis
Null Hypothesis (H0)
always states no difference between your groups
spread of estimates resulting from chance
Sampling Error
Indicates the precision of the estimate
Sampling Error
precise, accurate
imprecise, accurate
inaccurate, precise
inaccurate, imprecise
Two requirements to reduce bias
- Every unit in the population must have an equal chance of being included in the sample
- The selection of units must be independent of another
(The selection of any one member of the population must in no way influence the selection of any other member)
Our sample is unbiased
random sampling
a collection of individuals that are easily available to the researcher, biased
Sample of Convenience
describe membership (not measuring), qualitative
Categorical Variables
2 Types of Categorical Variables
- Nominal: No order
2. Ordinal: Order
measures that have magnitude on a numerical scale (measuring), quantitative
Numerical Variables
2 Types of Numerical Variables
- Continuous: think decimals
2. Discrete: whole numbers
Explanatory Variables
Independent, what is manipulated
Response Variables
Dependent, what is measured
Absolute Frequency
Looking at the absolute numbers
Relative Frequency
Looking at the proportion of individuals that fall within a particular category based on the entire study, patterns
the number of times each value of a variable occurs in a sample.
Frequency distribution
distribution of a variable in the whole population
Probability distribution
the distribution in the population is often approximated by a theoretical probability distribution
Normal distribution
researcher assigns treatments randomly to individuals
Experimental study
the assignment of treatments is not made by the researcher
Observational study
The result is that experimental studies can determine cause- and-effect relationships between variables, whereas observational studies can only point to associations, why?
Studies of the health consequences like voluntary cigarette smoking in people are all observational studies, because it is ethically impossible to assign smoking and nonsmoking treatments to people to assess the effects of smoking
