Stats Test 2 Prep
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Situation in which the outcome is unknown before
it happens...give example
 Random Experiment
 rolling die

This is the most basic outcome of a random experiment
(simple event)..give example
 Sample Point
 head or tail for a coin toss

This is a collection of sample points
Event

This is a collection of all sample points in the experiment
Sample space

The probability of an event (or simple event) is simply what you think it is , so long as the values of probability are observed...give example
 Personal probability
 flipping a coin and peaking

The probability of a (simple) event happening is
the “longrun” relative frequency of that event
Relative frequency interpretation

In the event that both A and B occur at the same time it is called an...
intersection

The probability of either A or B happening is called a ?
Union

Give the 2 terms assigned for when two events CANNOT happen at the same time
 Mutually exclusive
 disjoint

What is the formula for (A u B)
P(A)+P(B)P(A n B)

What is the formula for (A u B) if A and B are mutually exclusive..explain
 P(A)+P(B)P(A n B)=P(A)+P(B)
 this is because A n B can't happen together

What is the formula for conditional probability? (AB)
P(A n B)/P(B)

In the formula for AB can you calculate A n B directly?
No, it must be either given or extrapolated from a different formula

If knowledge of one event happening does not change the probability of the other one happening, the two events are said to be...
independent

What does this mean: A u B u C...
probability of at least one of these events have happening

What does this notation mean: A n B n C..
These events have all happened

What does this mean: A u B n C
Nothing..has no meaning...must know which one to do first

What does this notation mean: (A u B) n C
First the probability of the union of event A and B then the probability of the intersection of one of those with C

Based on the distributive rule, what does this equal: A u (B n C)
(A u B) n (A u C)

Based on the distributive rule, what does this equal: A n (B u C)
(A n B) u (A n C)

This is a sample that represents our population well
Representative sample

If a sample is not representative of the entire population, it is called:
biased

What are the 3 types of sample bias?
 Response bias
 Nonresponse bias
 Sampling bias

What is a response bias..give example
 Measurement obtained that is incorrect
 lies in a survey
 bad scale

What is a nonresponse bias?..give example
 Simply getting no response at all
 anything involving volunteer answers
 scale you can't use

What is Selection bias?...give example
 Taking a sample that is not from your general population
 Wanting a survey of the UConn population but only surveying grad students

How do you control sample bias
by taking simple random samples

A list of everything in your population is called a...
population frame

What is a convenience sample, and would it be a good representation?
 Simply sampling those around you at the time
 bad representation

What is cluster sampling?...and is it a good representation
 Breaking the population into groups and taking simple random samples of each group
 good representation

What is stratified sampling and how good of a representation is it?
 Breaking the population into different groups which have members with similar properties then doing SRS
 very good representation

This type of random variable can on a particular value
Discrete random variable

This type of random variable can take on any value in one or more intervals
Continuous random variable