Unit 1

Question 1

Categorical variable

Answer 1

Assigns labels that place individuals into a group or category

Question 2

Quantitative variable

Answer 2

Takes on numerical values where it makes sense to take an average

Question 3

Distribution

Answer 3

Tells us what values a variable takes on and how often they occur

Question 4

Frequency table

Answer 4

Shows number of individuals that have each attribute

Question 5

Relative frequency table

Answer 5

Shows proportion or percentage of individuals that have each attribute

Question 6

Marginal relative frequency

Answer 6

Total number of individuals in one category divided by table total

SEE page 8

Question 7

Joint Relative frequency

Answer 7

Individuals that belong to 2 categories divided by table total

SEE page 8

Question 8

Conditional relative frequency

Answer 8

Individuals in one category divided by total of another category

SEE page 8

Question 9

Conditional distribution

Answer 9

All the conditional relative frequencies listed together for a variable

SEE page 8

Question 10

Symmetric data plot

Answer 10

One peak (unimodal) and points are the the same on either side (symmetrical)

SEE page 14

Question 11

Skewed to the right data plot

Answer 11

One peak, data points are mostly on the left (the lower end)

SEE page 14

Question 12

Skewed to the left data plot

Answer 12

One peak, data points are mostly to the right (high side)

SEE page 14

Question 13

Unimodal plot

Answer 13

Data plot with one peak

SEE page 14

Question 14

Bimodal plot

Answer 14

Data plot with two peaks

SEE page 14

Question 15

Approximately Symmetric

Answer 15

Can have multiple peaks, but is roughly a symmetric plot

SEE page 14

Question 16

How to describe the distribution of a quantitative variable

Answer 16

SOCS!!!

Shape
Outliers
Center
Spread

***AP exam tip: include CONTEXT

Question 17

Histogram Def

Answer 17

A histogram shows each interval of values as a bar. The heights represent how many individuals are in each interval

NOT a bar graph
For QUANTITATIVE data

Question 18

Histogram Rules

Answer 18

Choose equal width for each bar
Draw and label each axis
Bars touch each other and y-axis
Scale the axes appropriately

Question 19

Mean

Answer 19

Average of a data set

Symbol: x̄

Question 20

Statistic

Answer 20

A value that describes a SAMPLE of data

Question 21

Parameter

Answer 21

A value that describes an entire POPULATION

Question 22

Resistant

Answer 22

A statistical measure that isn’t sensitive to outliers

Question 23

Median

Answer 23

Midpoint of the data set value where 1/2 data lies below and 1/2 data lies above it

Median IS resistant

Question 24

Comparing Median & Mean

Answer 24

If mean = median (symmetric)
If mean > median (skewed right)
If mean < median (skewed left)

Question 25

Range

Answer 25

Maximum — Minimum Range is a single value

Question 26

Standard deviation

Answer 26

Measures the average distance the data values are from the mean Symbol: Sx SEE page 24

Question 27

Standard deviation properties

Answer 27

Always ≥ 0 Larger Sx indicates larger variation NOT resistant to outliers Only use when mean is the chosen measure of center

Question 28

Sample variance

Answer 28

Standard deviation squared

Question 29

Quartiles

Answer 29

First quartile (Q1): Median of the first 1/2 of data Third Quartile (Q3): Median of the 2nd half of data Interquartile range (IQR): Range of the middle 50% of the distribution Formula: Q3 — Q1 (IS resistant)

Question 30

Outlier Rules

Answer 30

Low outlier < Q1 — (1.5 x IQR) High outlier > Q3 + (1.5 x IQR)

Question 31

Five number summary

Answer 31

Minimum Q1 Median Q3 Maximum

Question 32

Boxplots

Answer 32

Visual representation of the 5 number summary Drawn above one horizontal axis Box starts at Q1 and ends at Q3 Median is marked inside the box Whiskers start and ends at points low and high that are NOT outliers Outliers grouped at separate points