Module 1- Nature of Probability and Statistics

Question 1

What is an element?

Answer 1

An object contained in a set of data

Question 2

What is a variable?

Answer 2

A characteristic or attribute of that element capable of assuming any value within the data set

Question 3

What is data?

Answer 3

Values that the variable assumes

Question 4

What are random variables?

Answer 4

values are determined by chance

Question 5

What two categories is statistics divided into?

Answer 5

Descriptive and Inferential

Question 6

What is the definition of descriptive statistics?

Answer 6

consists of the collection, organization, summarization and presentation of data.

Question 7

What is the definition of Inferential statistics?

Answer 7

consists of generalizing from samples to populations, performing estimations and hypothesis tests, determining relationships among variables, and making predictions.

Question 8

What is a population?

Answer 8

consists of all subjects that are being studies

Question 9

What is a sample?

Answer 9

a group of subjects selected from a population

Question 10

Variables can be classified as what two categories?

Answer 10

Quantitative or Qualitative

Question 11

What are Qualitative variables?

Answer 11

variables that can be placed into distinct categories, according to some characteristic or attribute.
(eg. gender, religious preference, geographic location)

Question 12

What are Quantitative variables?

Answer 12

are numerical and can be ordered, ranked or measured.

eg, age, height, weight, body temperature

Question 13

What two categories can Quantitative variables be divided into?

Answer 13

Discrete and Continuous

Question 14

What are discrete variables?

Answer 14

assume values that can be counted

Question 15

What are continuous variables?

Answer 15

can assume an infinite number of values in an interval between any two specific values. They are obtained by measuring and often include decimals and fractions.
(eg, temperature)

Question 16

What are levels of measurement?

Answer 16

variables can be classified by how they are categorized, counted or measured.

Question 17

What are the 4 common types of measurement scales used?

Answer 17

Nominal, ordinal, interval and ratio

Question 18

Describe the nominal level of measurement?

Answer 18

classifies data into mutually exclusive, exhausting categories in which no order or ranking can be imposed on the data,

Question 19

What are 4 examples of nominal level of measurement?

Answer 19

Gender
religious affiliation
postal code
eye colour

Question 20

Describe the ordinal level of measurement?

Answer 20

classifies data into categories that can be ranked, however precise differences between the ranks do not exist.
No precise measurement!!

Question 21

What are some examples of ordinal level of measurement?

Answer 21

Grades
Rating scale (poor, good, excellent)
Race results (1st, 2nd, 3rd)
Income level (low, middle, high)

Question 22

Describe the interval level of measurement?

Answer 22

ranks data and precise differences between units of measure do exist, however, there is no meaningful zero.

Question 23

What are some examples of interval level of measurement?

Answer 23

IQ tests
Temperature
SAT or GMAT score
Calendar years

Question 24

Describe the ratio level of measurement?

Answer 24

possesses all the characteristics of interval measurement, and there exists a true zero.

Question 25

What are some examples of ratio-level data?

Answer 25

height
weight
volume
age
Salary
Time of Day
Distance
Precipitation

Question 26

What four ways can sample data be collected?

Answer 26

Telephone surveys
Mailed questionnaires
Personal interviews
Internet surveys

Question 27

What four basic methods of sampling do statisticians use to obtain unbiased samples?

Answer 27

Random
Systematic
Stratified
Cluster

Question 28

Describe random sampling?

Answer 28

Subjects are selected by random numbers

Question 29

Describe Systematic sampling?

Answer 29

subjects are selected by using every kth number after the first subject is randomly selected from 1 to k.
Example: if they were 2000 subjects in the population and a sample of 50 subjects was needed. (2000/50=40…therefore…k=40 and every 40th subject would be selected.)

Question 30

Describe stratified sampling?

Answer 30

Subjects are selected by dividing up the population into groups (strata), and subjects within the group are randomly selected.

Question 31

Describe cluster sampling?

Answer 31

Subjects are selected by using an intact group that is representative of the population.

Question 32

What are 3 ways to classify statistical studies?

Answer 32

Observational
Experimental
Quasi-Experimental

Question 33

Describe observational study?

Answer 33

the researcher merely observes what is happening or what has happened in the past and tries to draw conclusions based on these observations.

Question 34

Describe experimental study?

Answer 34

the researcher manipulates on of the variables and tries to determine how the manipulation influences other variables.

Question 35

Describe quasi-experimental study?

Answer 35

When random assignment is not possible, researchers use intact groups.

Question 36

Statistical studies usually include ______ independent variables and ______dependent variables?

Answer 36

one or more

one

Question 37

What is the independent variable?

Answer 37

is an experiential study is the one that is being manipulated by the researcher.
ALSO CALLED THE EXPLANATORY VARIABLE

Question 38

What is the dependent variable?

Answer 38

The response variable

ALSO CALLED OUTCOME VARIABLE