Ap Stats Unit 1 Part 1 Vocab

statistics

the science + art of collecting, analyzing, + drawing conclusions from data

variable

characteristics that can take different values for different individuals

individual

object or person that makes up a study’s sample

categorical variable

values are labels that place individuals into groups/categories (can be numerical)

quantitative variable

values are numbers that are quantities you count or measure (take average)

distribution

what value a variable takes and how often

frequency / frequency table

number of individuals in a specific value (table shows this

relative frequency / relative frequency table

relative frequency: proportion or % of individuals having each value in relation to the whole group (table shows this)

bar graph

shows each category as a bar; heights of bars show category or relative frequency; used with categorical data

pie chart

shows each category as a slice of “pie”; areas of the slices are proportional to relative frequency

side-by-side bar graph

displays the distribution of one categorical variable in each of 2+ groups; compares variable in categories and % is used when samples are not equal

discrete random variable

countable set of possible values with gaps between numbers (ex: shoe size)

continuous random variable

measurable or takes any value over an interval (ex: GPA)

dot plot

shows each value as a dot above a location on a number line

skewed distribution

goes Towards the Tail

uniform distribution

frequency of all data is about the same

stem plot

• stem: all digits but the last in a number

• leaf: only the right-most digit ordered least → greatest

histogram

shows each interval as an equal-width bar; used with quantitative data

median

middle number in a data set AFTER being ordered least → greatest

• odd number of data: middle number (ex: 1, 2, 3, 7, 10 med: 3)

• even number of data: middle 2 numbers averaged (1, 2, 4, 6, 7 10 med: 5)

mean

average of all numbers; taken by adding all numbers and dividing by number of numbers (ex: 1+3+5+5+2+8 / 6 mean: 6)

population

all individuals a astudy could affect

parameter

number about population

sample

selected group from population being studied

statistic

number about sample

resistant

not easily influenced or changed

range

interval where data falls; highest # - lowest number

quartile 1 (Q1) / quartile 3 (Q3) / interquartile range (IQR)

Q1: separates bottom 25% from upper 75%; middle of bottom half of data

Q3: separates top 25% from lower 75%; middle of upper half of data

IQR: Q3 - Q1; range of middle 50% of data

five number summary

minimum, Q1, IQR, Q3, maximum

standard deviation

typical distance of values in a distribution from the mean; measures variability in symmetric data w/ mean as a measure of center

box plot (aka box and whisker plot)

visual representation of the five number summary above a number line