Probability

Question 1

Probability of an event x

Answer 1

total number of outcomes in the experiment

Question 2

Sample Space

Answer 2

set of all possible outcomes

Question 3

Probability of a sample space

Answer 3

1

Question 4

Complementary event

Answer 4

two events that do not occur together; if one occurs the other one doesn’t

Question 5

P(A)+P(Not A)

Answer 5

1

Question 6

P(Not A)

Answer 6

1- P(A)[

Question 7

And in probability

Answer 7

multiply

Question 8

Two events A and B are independent

Answer 8

if the fact that event A occurs does not change the probability that B will occur and vice-versa

Question 9

P(A and B)

Answer 9

P(A) * P(B)

Question 10

Dependent events

Answer 10

if the occurrence of the first event affects the occurrence of the second event in such a way that the probability of the second event is changed

Question 11

P(A and B)

Answer 11

P(A) * P(B|A)

Question 12

Mutually exclusive

Answer 12

if the can not occur at the same time

Question 13

Addition rule concerning mutually exclusive events

Answer 13

P(A) + P(B)

Question 14

P(A or B)

Answer 14

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

Question 15

When an event has more than one possible outcome, each possible outcome must be considered when calculating the probability that the event will occur. Thus, to determine the actual probability we do the following

Answer 15

number of outcomes producing the event * probability of one outcome

*The shortcut can be used when each of the outcomes has the same probability

Question 16

At least

Answer 16

equal to or greater to

Question 17

Calculating at least probability problems

Answer 17

1) Define the scenarios
2) Calculate the probability of each scenario
3) Add together the probability of each scenario

Question 18

When a question asks for the probability that “at least 1” outcomes will occur, consider using

Answer 18

complementary events to simply the problem/

P(at least 1 outcome occurs)= 1- P(none of these outcomes occur)

Question 19

Two events that are not complementary

Answer 19

do not add up to 1

Question 20

Dependent probability with multiple outcomes, consider using the/formula

Answer 20

Probability of an event=
number of favorable outcomes
———————————————
total number of outcomes

combination method in which you separately calculate the numerator and denominator of

Question 21

Some items will or must be selected

Answer 21

#of ways that some numbers of items must be selected 
-------------------------------------------------------------------
# of ways that all items can be selected

Question 22

Favorable outcomes/ total outcomes (when some items must not be selected)

Answer 22

#of ways that some number of items must not be selected 
----------------------------------------------------------------------------
#of ways that all items can be selected

Question 23

When determining the number of ways that some number of items must not be selected

Answer 23

mentally eliminate from the main pool those items that are excluded from the subgroup. Remember restricting item from a subgroups does not change the number of spots available in that subgroups

Question 24

Probability is

Answer 24

a ratio

i.e: 1/4 -> there are x occurrence for every 4 occurrence