Collecting, organizing, summarizing and analyzing data.
Statistics provides a measure of...
The process of statistics... (4 things)
Identify, collect, organize, conclude
Numerical summary of population...
Numerical summary of sample...
Descriptive statistics describes data through... (3 things)
Numbers, graphs, tables
Name, label, category. Not ranked
Name, label, category. Is ranked
Name, label, category. Difference of rank is meaningful
Name, label, category. Difference of rank is meaningful and zero means the absence of quantity.
Explanatory variable affects the value of a
Measures response variable without changing the explanatory variables.
Observational studies allow researchers to claim _______ not ________
Not separating two explanatory variables
A variable that affects the response variable but is not considered
A researcher assigns the individuals in a study to a certain _group____, intentionally ___changes__ the value of the explanatory variable, and then records the value of the __response___variable for each group.
The data are collected by looking back in time or looking at existing records.
The data are collected over time.
Observational studies that collect information about individuals at a specific ___point_____ in time, or over a very ___short___ period of time
Cross sectional (Prospective)
These studies are retrospective. In case-control studies, individuals that have certain characteristics are matched with those that do not.
Case Control (Retrospective)
observed over a period of time. Over this time period, characteristics about the individuals are recorded.
process of using ___chance________ to select individuals from a population to be included in the sample.
equally likely ___chance____
Simple Random Sample
obtained by __separating________ the population into non-overlapping groups called strata and then obtaining ____a simple random sample_________ from each stratum.
obtained by selecting every kth individual from the population. The first individual selected corresponds to a random number between 1 and k.
Systematic sample- find k
N/n, round down to integer.
obtained by selecting all individuals within a randomly selected collection or group of individuals. One or more groups is chosen at random. All individuals in chosen group are sampled.
the technique used to obtain the individuals to be in the sample tends to ______Favor__ one part of the population _over___ another.
Convenience sample, voluntary response sample and undercoverage are _____ bias
exists when individuals selected to be in the sample who do not respond to the survey have different opinions from those who do
exists when the answers on a survey do not reflect the true feeling of the respondent.
Design in which each experimental unit is randomly assigned to a treatment
Completely Random Design
design in which the experimental units are paired up.
Matched Pairs Design
Design is used when the experimental units are divided into homogeneous groups