Stats_Exam 2

Question 1

Define a random experiment

Answer 1

an action whose outcome cannot be predicted with certainity. Each subject equally likely.

Question 2

Define a sample space

Answer 2

the collection of all possible outcomes for an experiment

Question 3

Define an Event

Answer 3

a collection of outcomes. A subset of a sample space.

Question 4

Define mutually exclusive

Answer 4

2 or more events, no 2 having anything in common

Question 5

Define independent events

Answer 5

may still have something in common, but does not affect the probability of the former event.

Question 6

Define the complement of an event

Answer 6

1- the probability the evend does not occur. Not A

Question 7

Descrime the union of 2 events

Answer 7

A can occur B can occur or Both can occur

Question 8

What is the intersection of 2 events

Answer 8

A and B occur simultaneously

Question 9

P(A) = 1 means..

Answer 9

the event is certain to happen

Question 10

P(A) = 0 neabs

Answer 10

the event will NOT happen

Question 11

What rule does this equation fall under:

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

Answer 11

Special Addition for mutually exclusive events

Question 12

The complementation rule formula

Answer 12

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

Question 13

What rule does this equation fall under:

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

Answer 13

General Addition Rule. Because it will always get you the right answer

Question 14

What is a contingency table?

Answer 14

• the distribution of one variable in rows another in columns
• study the association between the two variables

Question 15

the probability of one event occuring when it’s known that another one has occurred.

Answer 15

Conditional Probability

Question 16

Finish the equation P ( B | A)=

Answer 16

P(A & B) / P(A). (Pay attention to the sample size.) General Conditional Rule.

Question 17

When referring to the intersection of 2 events, What is the general rule?

Answer 17

P(A & B) = P(A) * P (B | A)

Question 18

What is the special conditional rule-

Answer 18

When A & B are independent events. P(B | A) = P(B)

Question 19

When referring to the union of 2 events. What is the special rule for independent events

Answer 19

P( A & B) = P(B) * P(A)

Question 20

What is a random variable?

Answer 20

a numerical value that’s determined by chance

Question 21

Define the probability distribution

Answer 21

the probabilities with which X takes those values

Question 22

How to remember greater than and less than….

Answer 22

the pointy end is facing the smaller one ex 9 >6

Question 23

When reading the equation, decide which formula to use before you plug in the equation

Question 24

If two events are mutually exclusive, what is their probability?

Answer 24

0

Question 25

If two events are independent what is the probabilty?

Answer 25

you must multiply them