statistics vocabulary (copy)

Convenience Sampling

choosing individuals from the population who are easy to reach results in a convenience sample

simple random samples (SRS)

a sample chosen in such a way that every group of n individuals in the population has an equal chance of being selected as the sample

cluster samples

population is divided into smaller groups, clusters, that are then randomly selected for the sample

systematic samples

researchers select members of the population at the same intervals (k) determined in advance

population

entire group of individuals we want info about

census

collects data from every individual in the population

sample

subset of individuals in the population from which we collect data

confounding

occurs when two variables are associated in such a way that their effects on a response variable cannot be distinguished from each other

parameter

number description of a population characteristic

statistic

number description of a sample characteristic

descriptive stats

branch of stats that involves the organization, summarization, display of data

inferential stats

branch of stats that involves a sample to draw conclusions about a population

Nominal Scale

classifies data into mutually exclusive (non-overlapping), exhausting categories in which no order or ranking can be imposed on the data

Ordinal Scale

classifies data into categories that can be ranked; however, precise differences between the ranks do not exist.

Interval Scale

ranks data, and precise differences between units of measure do exist; however, there is no meaningful zero.

Ratio Scale

possesses all the characteristics of an interval measurement, and there exist a true zero

Stratified Sampling

a method of sampling that involves the division of a population into smaller sub-groups known as strata.

Random Sampling

a subset of a statistical population in which each member of the subset has an equal probability of being chosen. Meant to be an unbiased representation of a group.

randomized block

subjects with similar characteristics into blocks

matched pair

paired up according to similarity; one recives treatment, other does not