AP Statistics (Unit 1)

Categorical Frequency distribution

nominal- or ordinal-level data that can be placed in categories

Histograms

the most common graph of distributions with one quantitative variable. It displays the data by using vertical bars of various heights to represent the frequency of the classes.

Frequency Polygon

It is a graph that displays the data by using lines that connect points plotted for the frequencies at the class midpoints

Relative Frequency Graph

they are used when the proportion of data values that fall into a given class is more important than the actual number of data values that fall into that class

Raw Data

Data collected in original form

Frequency distribution

the organization of raw data in table form using classes and frequencies

Individuals

Objects described by a set of data (eg: people, animals or things)

Variables

any characteristic of an individual

Exploratory Data analysis

statistical tools and ideas that can help examine data in order to describe their main features

Categorical

records which of several groups or categories an individual belongs to.

Quantitative

takes numerical values for which it makes sense to do arithmetic operations like adding and averageing.

distribution

of a variable tells us what values the variable takes and how often it takes these values (the pattern of variation of a variable)

Dot Plots

another name for a line plot, which is used to graph the distribution of data

Stemplots

an additional method of graphing a distribution of quantitative data (for small data sets) using a “stem” and a “leaf”

Overall pattern

a distribution that can be described by observing its center, spread and shape

Deviations

The difference between a value in a frequency distribution and a fixed number (as the mean).

Center

the value or description of the middle of the data

Spread

the extent of the data from the smallest to the largest

Shape

the approximate design of a distribution as either symmetric or skewed

Symmetric

the right and left side of a distribution of a graph are approximately mirror images of each other

skewed to the right

the upper half of the observations extends much father out than the left hall

skewed to the left

the lower half of the observations extends much farther out than the right half

Outliers

any graph of data is an individual observation that falls outside the overall pattern of the graph

time plot

of a variable plots each observation against the time at which it was measured

trend

a long time upward or downward movement over time

Descriptive Statistics

the collection organization, summarization, and presentation of data

Inferential Statistics

generalizing from samples to populations, performing estimations and hypothesis tests, determining relationships among variables and making predictions

Population

consists of subjects being studied

sample

a group of subjects selected from a population

Discrete variables

assume values can be counted

continuous variables

an infinite number of values between any two specific values