AP Statistics - Section 1F Vocabulary

inference

using sample statistics to estimate population characteristics/parameters

experiment

imposes treatments to experimental units to measure responses; best way to determine if a cause leads to an effect

response variable

measures outcome of study

explanatory variable

may explain changes in a response variable

factors

variables that are manipulated any may affect response variables

levels

different values of factors

treatment

specific condition applied to participants

experimental unit

item that treatment is assigned to (humans are called subjects)

one factor experiment

levels of factors are assigned to experimental units

multifactor experiment

combo of factor levels

observational study

studies individuals and variables of interest but does not impose any treatments

retrospective observational study

units from the past are selected

prospective observational study

units from the past are selected in addition to current units

survey

data collected from humans from a fixed set of questions

extraneous variable

variable(s) other than explanatory variable(s) that may also effect response variables

confounding variable

type of extraneous variable that could be associated with explanatory and response variables

random sampling

using chance process to choose a sample from a population

convenience sample

choosing based on personal judgement; not considered random

simple random sample

using tech to pick data

stratified sample

each sub group gets equal representation; homogeneous/similar groups (1 sample taken from each group)

cluster random sample

data is divided into groups randomly; heterogeneous/mixed groups (1sample taken from each group); used when grouping information about data is unknown

systematic sample

random starting location of data, then choose every kth value for the rest of the data until you return to beginning