chapter 1 ap stats

statistical problem solving process

formulate questions

collect data

analyze data

interpret results

what is statistics

collecting, analyzing, and drawing conclusions from data

retrospective studies

look backward at past events

prospective studies

look forward in time from the present

descriptive statistics

exploratory data analysis

observational unit

what you’re studying

variable

takes on different values for different individuals

categorical variable

labels that place each individual into a particular group called a category

quantitative variable

takes number values that are quantities, counts, or measurements

discrete variable

quantitative variable that takes fixed set of possible values with gaps between them

continuous variable

a quantitative variable that can take any value in an interval on the number line

parameter

number describing characterstics of population

statistic

number describing properties of sample

distribution

what values variable takes and how often it takes those values

how to display distribution of categorical data?

bar chart, pie chart, segmented bar chart

two way table

counts summarizing data on relationship between 2 categorical variables for some group of individuals

marginal relative frequency

percent or proportion of individuals that have a specific value for one categorical variable

joint relative frequency

percent or proportion of individuals with specific value for one categorical variable and a specific value for another categorical variable

conditional relative frequency

percent or proportion of individuals that have a specific value for one categorical value among individuals who share the same value of another categorical variable (the condition)

conditional distribution

among environmental club members

comparing groups of different sizes

use relative frequencies instead of frequencies when analyzing categorical data

segmented bar chart

distribution of categorical variable as segments of a rectangle, with area of each segment proportional to the percent of individuals in the corresponding category

side-by-side bar chart

distribution of categorical variable for each value of another categorical variable. bars are grouped together based on the values of one of the categorical variables and placed side by side