Ap Stats Semester 1 Exam

Front 1

individuals

Back 1

are the objects described by a set of data.

Front 2

variable

Back 2

any characteristic of an individuals.

Front 3

categorical variable

Back 3

places an individual into one of several groups or categories. (distribution is measured in count or percent)

Front 4

quantitative variable

Back 4

takes numerical values for which arithmetic operations such as adding and averaging make sense.

Front 5

distribution

Back 5

tells us what values the variable takes and how often it takes these values.
use words like center,spread and shape.

Front 6

outlier

Back 6

an individual observation that falls outside the overall pattern of the graph.

Front 7

symmetric

Back 7

the left and right sides are mirror images.

Front 8

skewed to the right

Back 8

if the right sides extends farther out then the left side. (tail off to the right)

Front 9

skewed left

Back 9

if the left side of the histogram extends much farther out than the right side. (tail off to the left)

Front 10

P-th percentile

Back 10

the value such that p percent of the observations fall at or below it.

Front 11

relative frequency

Back 11

count per class/total x 100%

Front 12

cumulative frequency

Back 12

add the counts of the current class and all classes below that level (add classes together as each class increases)

Front 13

relative cumulative frequency
(ojive graph)

Back 13

cumulative frequency per class/total x100%

Front 14

IQR

Back 14

Q3-Q1= ?
where Q3 is the median of all observations to the RIGHT of the overall median and
Q1= median of all observations to the LEFT of the overall median.

Front 15

upper outlier cut off

Back 15

Q3 + (1.5 X IQR)

Front 16

lower outlier cut off

Back 16

Q1 - ( 1.5 x IQR )

Front 17

5 number summary

Back 17

minimum , Q1, Median, Q3, Maximum

Front 18

standard deviation

Back 18

the distance of #s from the mean

Front 19

density curve

Back 19

is always on or above the horizontal axis and has an area of exactly 1 underneath it. THE MEDIAN SPLITS THE CURVE IN HALF.
THE MEAN IS THE POINT AT WHICH THE CURVE WOULD BALANCE.

Front 20

response variable

Back 20

measures an outcome of a study

Front 21

exploratory variable

Back 21

attempts to explain the observed outcomes. (independent variable)

Front 22

scatterplot

Back 22

shows the relationship between two quantitative variables measured on the same individuals.

notice the: overall pattern, strength, form, and outliers

Front 23

regression line

Back 23

a straight line that describes how response variable y changes as an explanatory variable x changes.

Front 24

coefficent of determination

Back 24

r2-ed

Front 25

residuals

Back 25

the difference between an observed value and predicted value.

Front 26

linear growth

Back 26

increases by a fixed amount

Front 27

exponential growth

Back 27

increases by a fixed percentage

Front 28

extrapolation

Back 28

the use of a regression line for prediction far outside the domain of values of the x and y

Front 29

lurking variable

Back 29

not among the x and y variables but may influence the interpretations of the relationship between x and y

Front 30

are usually too high when applied to individuals

Back 30

correlations based on averaged data.

Front 31

simpsons paradox

Back 31

the reversal of the direction of a comparison or an association when data from several groups are combined to form a single group.

Front 32

observational study

Back 32

observes individuals and measures variables of interest but does not influence responses.

Front 33

experiment

Back 33

deliberately imposes some treatment on individuals in order to observe their responses.

Front 34

population

Back 34

the entire group of individuals we want information about.

Front 35

sample

Back 35

part of the population that is actually examined.

Front 36

census

Back 36

attempts to contact every individual in the entire population.

Front 37

voluntary response sample

Back 37

consists of people who choose themselvers by responding to a general appeal. BIASED - brings out especially those with negative opinions

Front 38

convenience sampling

Back 38

chooses individuals easiest to reach - BIASED

Front 39

biased

Back 39

systematically favors certain outcomes.

Front 40

SRS or simple random sample

Back 40

eveyrone in the population has an eaqual chance of being chosen.

Front 41

strata

Back 41

groups of similar individuals