Exam 1 Material

Question 1

In words, express what the Union formula means using events A and B.

Answer 1

The probability that A or B occurs is the P that A occurs plus the P that B occurs minus the P that both A and B occurs (A intersection B).

Question 2

Two events are mutually exclusive if:

Answer 2

they do not intersect. They have no outcomes in common.

Question 3

Express when two events, A and B, are mutually exclusive.

Answer 3

P(A or B)= P(A)+P(B)-0

Question 4

Two events are independent if:

Answer 4

the occurence or non-occurence of one does not change the P that the other will occur.

Question 5

Express when the P of two events, A and B, are mutually independent.

Answer 5

P(A and B)= P(A)*P(B)

Question 6

Express when the P of two events, A and B, are mutually dependent.

Answer 6

P(A and B)= P(A)*P(B/A)

Question 7

Addition Law of Probability:

For any events A and B:

Answer 7

P(A U B)=P(A)+P (B)-P(A ∩ B)

Question 8

Addition Law of Probability:

For A, B, mutually exclusive:

Answer 8

P(A U B)=P(A)+P(B)

Question 9

Addition Law of Probability:

For A, B, independent:

Answer 9

P(A U B)=P(A)+P (B)-P(A)*P(B)

Question 10

The probability that someone who is known to be overweight is hypertensive would be written as

Answer 10

P(Hypertensive/Overweight)=P(H/O).

Question 11

If P(A/B)=P(A)

Answer 11

Then they are independent.

Question 12

If P(A∩B)=P(A)*P(B)

Answer 12

Then they are independent.

Question 13

When two events are mutually exclusive, they are ALWAYS

Answer 13

Dependent.

Question 14

If P(A/B)=P(A), then what can be said about B?

Answer 14

B had no impact on A, and A and B are independent.

Question 15

If P(A and B)=P(A)*P(B), then what can be said about events A and B?

Answer 15

They are independent.

Question 16

In probability theory, a set of events is collectively exhaustive if:

Answer 16

it includes all possible outcomes.

Question 17

Descriptive Statistics deals with _____ and contains a ____ and ____

Answer 17

the organizing and summary of data; parameter and statistic.

Question 18

A parameter is

Answer 18

a number that describes some characteristic of a population.

Question 19

A statistic

Answer 19

is a number that we can calculate purely from a sample.

Question 20

Inferential Statistics deals with

Answer 20

Using sample statistics to draw inferences about population parameters

Question 21

Sampling techniques include:

Answer 21

Simple random sampling, stratified random sampling, 1 in k systematic sampling, cluster sampling, and convenience sampling..

Question 22

In simple random sampling,

Answer 22

Each member of the population has the same chance of being selected for the sample, and Every possible sample of the size n has the same chance of being selected to represent the population.

Question 23

In stratified random sampling:

Answer 23

members of the population are divided into two or more homogeneous subsets, called strata, that share a similar characteristic such as age, gender, ethnicity, political preference.

Question 24

In 1 in k systematic sampling:

Answer 24

A starting number is randomly selected from amongst the first k members, and then every “kth” member is selected from the starting number,

Question 25

In cluster sampling:

Answer 25

divide the population into groups called clusters, then randomly select some of these clusters, and include each member of that cluster in the sample. The cost per sample point is less for cluster sampling than for other sampling methods.

Question 26

Convenience sampling:

Answer 26

simply uses results or data that are conveniently and readily available. This technique is biased.

Question 27

A categorical variable:

Answer 27

places an individual into one of a group of categories. (Cannot be measured on a numerical scale.)

Question 28

A quantitative variable

Answer 28

takes on numerical values on which arithmetic operations can be performed.

Question 29

Categorical data includes:

Answer 29

Nominal, and Ordinal information.

Question 30

Quantitative data includes:

Answer 30

Interval, and ratio information.

Question 31

Nominal information

Answer 31

consists of names only or qualities with no implied criteria by which we can identify which data item is greater than or less than another. (No numerical computation is possible.)

Question 32

Ordinal information

Answer 32

may be arranged in some order but actual differences between data values either cannot be determined, or are meaningless.

Question 33

Interval information

Answer 33

have meaningful differences between data values. However, there is no Intrinsic ‘0’ or start point, and ratios of data values are not meaningful.

Question 34

Ratio information

Answer 34

has Meaningful differences exist between data values. Includes an inherent ‘0’ or start point. ‘0’ reflects the absence of the measured characteristic, Ratios are meaningful.