Chapter 4

Question 1

Rare event rule for inferential statistics

Answer 1

if the probability of an event is very small, yet it happens anyways, we will tend to question our previous assumption

Question 2

concept of probability

Answer 2

an exact fraction or decimal between 0 and 1

Question 3

rounding rule for probability

Answer 3

round to 3 sig figs, if not an exact number

Question 4

event

Answer 4

a collection of items from a situation

Question 5

simple event

Answer 5

specific type of event that can be broken down into multiple items

Question 6

sample space

Answer 6

everything that can happen when an experiment is conducted

Question 7

probability notation

Answer 7

probability of A = P(A)

Question 8

relative frequency approximation of probability

Answer 8

probabilities computed using observations

Question 9

classical approach to probability

Answer 9

computed when equally likely outcomes happen [e.g. P(odd) on a dice]

Question 10

subjective probability

Answer 10

estimated by recent events and prior knowledge

Question 11

law of large numbers

Answer 11

as we continue to perform an experiment over and over again, the probabilities will become exact.

Question 12

compliment

Answer 12

all items in a sample space that were not used by the original event

Question 13

unusual number of outcomes

Answer 13

when the outcome is far below or above what is expected

Question 14

compound event

Answer 14

2 or more simple events combined

Question 15

formal addition rule

Answer 15

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

Question 16

initiative addition rule

Answer 16

method that allows us to find the probability of an “or” event without the formula

Question 17

disjoint events

Answer 17

2 events that cannot happen at the same time

Question 18

addition rule for complimentary events

Answer 18

all probabilities in a sample space add together = 1

Question 19

independent events

Answer 19

the first event doesn’t change the outcome of the second event

Question 20

dependent events

Answer 20

the first event changes the outcome of the second event

Question 21

formal multiplication rule

Answer 21

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

Question 22

intuitive multiplication rule

Answer 22

if events are dependent, we will adjust the probabilities as we multiply

Question 23

5% guideline for cumbersome calculations

Answer 23

if the sample size is less than 5% of the population, then treat dependent situations as independent situations for the sake of computation

Question 24

conditional probability

Answer 24

probability found with the knowledge that some other event has already happened

Question 25

permutation

Answer 25

when the order of the items matter toward the number of different outcomes

Question 26

combination

Answer 26

order does not matter toward the number of outcomes

Question 27

fundamental counting rule

Answer 27

if first event can happen m ways, and the second event can happen n ways, then together they can happen (m)(n) ways