AP Stats First Terms

population

The entire collection of individuals or objects about which information is desired

parameter

a numerical summary of a population, such as a mean or standard deviation.

sample survey

a study that collects data from a subset of a population to estimate characteristics of the whole population; subset of population

dot plots

a type of graphical display that uses dots to represent the frequency of data points in a dataset, allowing for easy visualization of distribution and trends.

stem plots

a method for displaying quantitative data that uses stems (the leading digits) and leaves (the trailing digits) to organize and visualize the data distribution.

box plots

displays quantitative data in quartiles with a box (Q1, Q2/Mean, Q3) and smallest and largest with whiskers

placebo

a harmless substance given to patients in a clinical study to research the effects of belief

inference

process of using data from a sample survey to conclude for a larger group of people

statistic

characteristic of a sample; used to create parameters

sample

a set of observations drawn from a population.

bar chart

graphical representation of data using rectangular bars where its length is proportional to its value

components of experimental design

manipulation, control, and random assignment

census

a study that obtains data from every member of a population

probability

the likelihood for something to occur

controlled experiment

a baseline group that receives no treatment or a neutral treatment

selection bias

Undercoverage occurs when some members of the population are inadequately represented

Voluntary response bias occurs when sample members are self-selected volunteers

Nonresponse bias occurs when individuals chosen for the sample are unwilling or unable to participate in the survey

histograms

representations of data distribution, where data is grouped into bins or intervals, and the frequency of data points within each bin is represented by the height of bars

explanatory vs. response variables

IV vs DV - explanatory causes outcomes which are the response

treatments

combination of explanatory variables (# of V1 and # of V2)

sample space

set of elements that represents all possible outcomes of a statistical experiment

observational study

attempt to understand relationships. However, unlike experiments, the researcher is not able to control subjects and/or treatments (variables) each group receives

response bias

bias that results from problems in the measurement process

Leading questions. The wording of the question may be loaded in some way to unduly favor one response over another

Social desirability. Most people like to present themselves in a favorable light, so they will be reluctant to admit to unsavory attitudes or illegal activities

measures of center

single values used to describe the middle or typical point of a data set

mean, mode, median

random sampling methods

the selection of a sample unit is based on chance and every element of the population has a known, non-zero probability of being selected; randomly selected sample unit to remove bias

blocking

used in a randomized block experiment to sort experimental units into homogeneous groups, called blocks. The goal of blocking is to create blocks such that dependent variable scores are more similar within blocks than across blocks; sorting results to stay organized

blinding

not telling subjects in a placebo experiment that they are taking a placebo to gain an equal effect on placebo vs no placebo

types of data/variables

quantitative - numerical data (discrete = whole numbers [objects], continuous = any number [property]

qualitative - categorical data (nominal [color, gender], ordinal = group with logical order [quality, rank]

2-way tables/contingency table

useful tool for examining relationships between categorical variables usually demonstrating frequencies

measures of spread (variability)

describe how far apart or close together data points are in a data set

standard deviation, range, variance, interquartile range (IQR)

measures of position

statistical tools that show where a specific data value fits inside a whole data set. can help spot outliers

quartiles, deciles, percentiles, z-scores

sample mean

the average value of a small group of data taken from a larger set/sample

population mean

the true average value of the data set