COMPLETE AP EXAM STUDY GUIDE

Question 1

discrete vs. continous variable

Answer 1

discrete: measurable in a fixed set of values (countable things like the number of students in a class)

continuous: can take any value (measurable things like weight or time)

Question 2

describing distributions

Answer 2

SOCS
shape: skewed, symmetrical, etc (use -ly words like slightly or moderately)
outliers: identify and state
center: mean with symmetric, median with skewed
spread: range or SD

Question 3

IQR/median when data is ___, mean/SD when data is ___

Answer 3

skewed, symmetric

Question 4

t/f: IQR is outlier resistant

Answer 4

true

Question 5

IQR calculation

Answer 5

q3 - q1

Question 6

how to make a box plot

Answer 6

use 5 number summary: min, q1, median, q3, and max

Question 7

outlier calculations

Answer 7

high: q3 + 1.5 (IQR)
low: q1 - 1.5 (IQR)

Question 8

t/f: box plots accurately describe shape

Answer 8

false, they do not, but they can be used if necessary

Question 9

side by side graph definition

Answer 9

displays the distribution of two categorical variables, the bars are grouped together and placed side by side

Question 10

segmented bar graph definition

Answer 10

measures a categorical variable as segments of a rectangle

Question 11

mosaic plot definition

Answer 11

segmented bar graph but the width is proportional to the number of individuals

Question 12

adding a constant “a” to a distribution does what

Answer 12

adds “a” to center and quartiles
spread (SD, IQR, variance) is unchanged

Question 13

variance calculation

Answer 13

the square root of SD

Question 14

multiplying by a constant “b” to a distribution does what

Answer 14

center is multiplied by “b”
SD and IQR are multiplied by |b|
variance is multiplied by b^2

Question 15

the values in a density curve always add up to

Answer 15

1

Question 16

when a distribution is symmetric, what is the relationship between the mean and median

Answer 16

mean = median

Question 17

when a distribution is skewed left, what is the relationship between the mean and median

Answer 17

mean < median

Question 18

when a distribution is skewed right, what is the relationship between the mean and median

Answer 18

mean > median

Question 19

what percentage of values falls within 1 SD of a normal distribution

Answer 19

68

Question 20

what percentage of values falls within 2 SD of a normal distribution

Answer 20

95

Question 21

what percentage of values falls within 1 SD of a normal distribution

Answer 21

99.7

Question 22

what is percentile

Answer 22

the percent of data below a certain data value

Question 23

q1 is what percentile

Answer 23

25

Question 24

median is what percentile

Answer 24

q2

Question 25

q3 is what percentile

Answer 25

75

Question 26

z score definition

Answer 26

standardizes data, measures how many standard deviations a data point is above or below a mean

Question 27

z score formula

Answer 27

data point - mean ---------------------------- standard deviation

Question 28

describing scatterplots

Answer 28

DUFS direction: positive or negative unsual features: clusters, outliers, etc form: linear, nonlinear strength: how close the points are together

Question 29

correlation has to have quantitative/qualitative variables

Answer 29

quantitative

Question 30

t/f: correlation = causation

Answer 30

false

Question 31

correlation is/not resistant to outliers

Answer 31

is not

Question 32

correlation is only used for ___ relationships

Answer 32

linear

Question 33

what is the symbol for the coef of determintation

Answer 33

r^2

Question 34

what is the coef of determination

Answer 34

how much variation in the y-values can be explained by the LSRL

Question 35

LSRL equation

Answer 35

y(hat) = a + bx

Question 36

what is a in the LSRL

Answer 36

y-intercept

Question 37

what is b in the LSRL

Answer 37

slope

Question 38

what is a residual

Answer 38

the difference between an observed value of the response variable and the value predicted by the LSRL

Question 39

how is a residual calculated

Answer 39

actual - predicted

Question 40

slope formula for LSRL

Answer 40

b = r (sy/sx)

Question 41

t/f: the slope passes through (xbar, ybar)

Answer 41

true

Question 42

y intercept formula for LSRL

Answer 42

a = ybar - b(xbar)

Question 43

interpreting the coef of determination

Answer 43

about ___ percent of the variability in (y-context) can be explained by the LSRL when x is ___