AP STATS

Individuals

Objects described by data

variable

any characteristic of an individual

Distribution

Tells us values of variables and how often they appear

Categorical variable

Descriptive variable thta doesn’t use numbers

Types of graphs categorical variables use ( 4 )

Pie chart, Bae graph, two way tables, segmented bar graph

Distributions of categorical variable

Frequency table, relative frequency table, a marginal discretion or conditional distribution

Relative frequency

Add up all the frequencies and divide it by the total number of data points

Conditional distribution

Distribution of percent correct given that smth, so like the rows

Marginal distribution

Percentages out of the totals, so like totals v totals

Examples of graphs used for quantative data

Dotplot, stemplot, histogram, boxplot

SOCS

Shape, outliers center spread

How to find mean

Add all data then divide by number of points

How to find median

N-1/2

5 number summmary

Max, min, median, Q1, Q3

If distribution is symmetric use

Mean and standard deviation

If distribution is skewed use

Median and IQR

Continuous variable

Variables that can have decimals within the intervals

Discrete variables

Variables that have whole number intervals between them

Percentiles

Shows data’s relative position

How to calculate percentile for x

Number of values o less than x/ total data points all times 100

Culmulative frequency

Chart that shows the popularity or mode of a certain type of data and the likelihood that a given event will fall below the frequency distribution

Z score

How many standard deviations away from the mean

Transformations : adding or subtracting

Affects center but not spread or shape

Transformations : multiplication or division

Affects center and spread but not shape

Density curve

Distributes overall pattern of distribution

standard deviation rules for a normally distributed curve

68-95-99.7

acronym to describe scatterplot

DOFS - direction, outliers/unusual features, form and strength

how to solve for residuals

actual - predicted or y - yHAT