AP Stat Summer Assignment Vocabulary

population : the total set of observations that can be made

sample : a set of observations drawn from a population

random sampling : a procedure for sampling from a population in which (a) the selection of a sample unit is based on chance and (b) every element of the population has a known, non-zero probability of being selected

simple random sampling (SRS) : any sampling method that has the following properties:-population consists of N objects-the sample consists of n objects-all possible samples of n objects are equally likely to occur

systematic random sampling : method where we create a list of every member of the population. From the list, we randomly select the first sample element from the first k elements on the population list. Thereafter, we select every kth element on the list.

multistage sampling : method where we select a sample by using combinations of different sampling methods. For example in stage one, we might use cluster sampling to choose clusters from the population. Then, in stage two, we might use simple random sampling to select a subset of elements from each cluster for the final sample.

experimental design : A plan for assigning subjects to treatment conditions. A good one serves three purposes.-Causation: it allows the experimenter to make casual inferences about the relationship between independent variables and a dependent variable.-Control: it allows the experimenter to rule out alternative explanations due to the confounding effects of extraneous variables.-Variability: it reduces variability within treatment conditions, which makes it easier to detect differences in treatment outcomes.

confounding : this occurs when the experimental controls do not allow the experimenter to reasonably eliminate plausible alternative explanations for an observed relationship between independent and dependent variables.

random assignment (randomization) : The practice of using chance methods (random number tables, flipping a coin, etc) to assign subjects to treatments.

completely randomized design : The simplest experiment design, in terms of data analysis and convenience. With this design, subjects are randomly assigned to treatments.