STT. Exam 2

Question 1

conditional probability formula

Answer 1

=Pr(little |big)

Question 2

false positive:

Answer 2

test states the condition is present, but it is actually absent

Question 3

false negative:

Answer 3

test states the condition is absent, but it is actually present

Question 4

sample space

Answer 4

“S”, set of all possible outcomes

Question 5

law of large numbers

Answer 5

the larger the number of trials, the more stable the probability will become

Question 6

independent trials

Answer 6

outcomes do not affect each other

Question 7

event

Answer 7

subset of sample space, ex. A {2,4,6}

Question 8

probability

Answer 8

count in event (ex. A)/ total in S

Question 9

probability is between two numbers:

Answer 9

0 and 1

Question 10

certain event

Answer 10

the probability of an event that must occur, is 1

Question 11

not A:

Answer 11

event that A does not occur

Question 12

A and B:

Answer 12

both A and B occur (what overlaps!)

Question 13

A or B:

Answer 13

event that both occur (don’t count overlap twice)

Question 14

disjoint/mutually exclusive A and B means that:

Answer 14

they have no overlap

Question 15

disjoint/mutually exclusive A and B formula:

Answer 15

P(A or B)= P(A and B) or P(A) + P(B)

Question 16

A and B formula when trials are independent:

Answer 16

P (A and B)= P(A) x P(B)

Question 17

complement rule:

Answer 17

P(not A or A compliment)= 1- P(A)

Question 18

If A and B are disjoint, then…

Answer 18

P(A and B) = 0

Question 19

If Pr(A and B) do not equal 0, then…

Answer 19

A and B are not disjoint

Question 20

or=

Answer 20

add

Question 21

and=

Answer 21

multiply

Question 22

if A and B are independent, then:

Answer 22

P(A and B) = P(A) x P(B)

Question 22

marginal

Answer 22

looking at columns, going “down”

Question 23

conditional

Answer 23

looking at rows, going “across”

Question 23

if A and B are dependent, then:

Answer 23

Pr(A and B) = Pr(A) x Pr(B|A)
Pr(A and B) = Pr(B) x Pr(A|B)

Question 24

X=

Answer 24

random variable

Question 25

E(X)=

Answer 25

expected value, mu, population mean

Question 26

population mean notation:

Answer 26

mu

Question 27

population SD notation:

Answer 27

sigma

Question 28

sample mean notation:

Answer 28

x bar

Question 29

sample SD notation:

Answer 29

s (little s)

Question 30

important property of density curve:

Answer 30

areas under the curve correspond to relative frequencies

Question 31

SD rule:

Answer 31

68% is 1 SD away
95% is 2 SD away
99.7% is 3 SD away

Question 32

z-score formula:

Answer 32

x-xbar/SD

Question 33

chap. 6 z-score formula:

Answer 33

x-mu/sigma

Question 34

68% of data:

Answer 34

mu + or - sigma

Question 35

95% of data:

Answer 35

mu + or - 2sigma

Question 36

99.7% of data:

Answer 36

mu + or - 3sigma

Question 37

center:

Answer 37

mu

Question 38

spread:

Answer 38

sigma

Question 39

area under the density curve represents the:

Answer 39

probability

Question 40

normal distribution/ ‘N’ formula:

Answer 40

= N(center, spread)
=N(mu, sigma)

Question 41

standard normal notation for mu:

Answer 41

0

Question 42

standard normal notation for sigma:

Answer 42

1

Question 43

x follows what notation:

Answer 43

general normal, x=N(mu, sigma)

Question 44

z follows what notation:

Answer 44

standard normal, z= N(0,1)

Question 45

lower tail:

Answer 45

to the left

Question 46

upper tail:

Answer 46

to the right

Question 47

what tail is used to find percentiles?

Answer 47

lower tail (to the left)

Question 48

population proportion:

Answer 48

p

Question 49

sample proportion:

Answer 49

p-hat

Question 50

sigma of p-hat formula:

Answer 50

square root of p times 1 - p-hat, all over n

Question 51

SD rules for p-hat:

Answer 51

68%= p + or - SD formula
95%= p + or - 2 times the SD formula
99.7%= p + or - 3 times the SD formula

Question 52

z-score p-hat formula=

Answer 52

= p-hat - p/ SD formula

Question 53

sampling distribution notation for p-hat=

Answer 53

= N(p, SD formula)