Stat 1

A numerical study of a sample

a numerical summary of a poplulation

the enitre group of individuals being studied

a subset of the population being studied

allow for classification of individuals based on some attribute or characterisitic

a quantitative variable that has either a finite number of possible values or a countable number of possible values. the term countable means that the values result from counting, such as 0,1,2,3,4 and so on.

a quantative variable that has an infinite number of possible values that are not countable. Example 0.023,1.25

are observations corresponding to a quantative variable

n=size of sample

measures the value of the response variable without attempting to influence the value of either the response or explanatory variables. That is, an observational study, the researcher observes the behavior of the individuals in the study without trying to influence the outcome of the study.

Observational study

is a list of all individuals in a population along with certain characteristics of each individual.

the process of using chance to select individuals from a population to be included in the sample.

random sampling

a sample of size n from a population of size N is obtained through sample random sampling. If every possible sample size of n has an queally likely chance of occuring the sample is then called simple random sampling.

is obtained by seperating the population in nonoverlapping groups called strata and then obtaining a simple random sample from each stratum. The individuals within each stratum should be homogeneous in some way.

is obtained by selecting every kth individual from the population. the first individual selected corresponds to a random number between 1 and k

is obtained by selecting all individuals within a randomly selected collection or group of individuals.

cluster sampling