Module 0 & 1

Question 1

What is a study unit?

Answer 1

individuals, subjects, or participants about which information is required on or on which measurements are recorded
the “Who” component of research

Question 2

What is population size (N)?

Answer 2

total number of individuals or items in the population under study

Question 3

What is a census?

Answer 3

collecting data about the entire population, but it’s usually too expensive or impossible

Question 4

What is a sample?

Answer 4

a subset of the population from which information is obtained

Question 5

What is sample size (n)?

Answer 5

number of study units, individuals, or observations in a single sample

Question 6

What a parameter?

Answer 6

a descriptive measure of a population

Question 7

What is a statistic?

Answer 7

a descriptive measure of a sample, used to estimate parameter

Question 8

What is a variable?

Answer 8

any characteristic that varies from one study to another

the “What” component of research

Question 9

What is a categorical variable?

Answer 9

a non-numerically valued variable that does not follow an ordered scale
nominal scales may sometimes be assigned numbers for ease of recording, but the value is still categorical
Example: 1 = single, 2 = married, 3 = divorced, etc.

Question 10

What are ordinal scale variables/data?

Answer 10

can be put in order from lowest to highest, but which don’t have a constant interval between successive units
Example: 1 = very poor, 2 = poor, 3 = moderate, 4 = good, 5 = very good
you can’t compare the distance between 1 and 2 so it’s not quantitative

Question 11

What are quantitative variables/data?

Answer 11

a numerically-valued variable

constant interval size between successive units

Question 12

What are discrete or discontinuous quantitative variables?

Answer 12

possible values only take on specific values, usually whole numbers
countable variables
example: number of people, animals, stars

Question 13

What are continuous quantitative variables?

Answer 13

infinite number of possible values between any observed range
example: the weight of a person may be 71 kg, 72 kg, 71.42 kg, 71.42893 kg

Question 14

What is an explanatory variable?

Answer 14

variables of interest that are hypothesized to explain or affect other variables in the study, but which are not likely to be affected by those other variables

Question 15

What is a response variable?

Answer 15

is measured or recorded for all experimental units in the treatment and control groups to see if these variables are affected by the predictor variables

Question 16

What is an extraneous variable?

Answer 16

are controlled or made constant for all treatment and control groups

Question 17

What are spatial aspects of design?

Answer 17

the “Where” component
involves the way the observations or replicates are arranged in space (distance, area, or volume)
linked to the study unit

Question 18

What are temporal aspects of design?

Answer 18

the “When” component
involves the way observations or replicates are arranged in time
start, end, frequency, of recording the variables

Question 19

What are techniques and methods of data collection?

Answer 19

the “How” component
specific methods and techniques used to make measurements of the variables or to record data
specialized for any given field of research

Question 20

What does adequate sample size depend on?

Answer 20

the characteristic you’re measuring
how frequently it occurs in the population
degree of variability of the material or objects being studied
precision of the techniques used
magnitude of the difference you expect to find between groups

Question 21

What is sample variability?

Answer 21

the differences or variation in the characteristics of interest from one sample to another from the same population

Question 22

What is a pilot study?

Answer 22

conducting a small trial run of a survey in order to design sampling strategy, test the questionnaire, test data recording technique

Question 23

What is random sampling?

Answer 23

all individuals have an equal chance of selection

the selection of individuals is independent

Question 24

What is simple random sampling (SRS)?

Answer 24

every individual is selected completely randomly and independently

Question 25

What is systematic random sampling?

Answer 25

the first sample is selected randomly, then all other samples are selected sequentially example: every fifth person

Question 26

What is stratified random sampling?

Answer 26

the population is divided into strata, based on a pilot study or some prior information sampling intensity in each stratum is proportional to the estimated density of the items in the stratum or size of the stratum

Question 27

What is multistage random sampling?

Answer 27

example of sampling leaves on trees of certain species randomly sample trees then, randomly sample the branches on the selected trees then, randomly sample some of the leaves from the selected branches

Question 28

What is cluster random sampling?

Answer 28

example: a company with a large number of apartment blocks wants to survey tenants, randomly select a few apartment blocks and then interview all the tenants in the selected blocks each selected block would be a cluster

Question 29

What is convenience sampling?

Answer 29

selected individuals for recording data simply because they are convenient to observe information from or question

Question 30

What is voluntary response bias?

Answer 30

asking for volunteers to participate in a social survey people who favor something are likely to volunteer not very random

Question 31

What is response bias?

Answer 31

questions in a social survey that appear to suggest or prompt a particular response favored by the researcher may also result from a poorly worded question

Question 32

What is nonresponse bias?

Answer 32

occurs when a large fraction of those sampled fail to respond to some or any of the questions

Question 33

What is an observational study or survey?

Answer 33

researcher collects data about a particular phenomenon as it occurs in nature or in society

Question 34

What is a population inference?

Answer 34

can be made if there is random selection from the target population

Question 35

What is a causal inference?

Answer 35

can be made if there is random assignment to treatment and control groups

Question 36

What is prospective observational study?

Answer 36

subjects identified beforehand, and data is recorded as the study proceeds

Question 37

What is retrospective observational study?

Answer 37

subjects identified and data recorded after the events have already occured

Question 38

What are treatment groups?

Answer 38

exposed to new conditions

Question 39

What are control groups?

Answer 39

exposed to the usual level of the manipulated variable or not exposed at all

Question 40

Why is replication required?

Answer 40

check or confirm the results apply the statistical analysis estimate the precision or state the probability that the conclusion is correct increase the power of the test

Question 41

What is completely randomized design (single factor)?

Answer 41

test units are allocated completely randomly to experimental treatments or plots

Question 42

What is paired design?

Answer 42

sometimes two populations are paired in space or time by some relationship example: taking measurements from the same patient of some variable such as blood pressure before and after treatment with a drug

Question 43

What is randomized block design?

Answer 43

liked paired design, but with more than two tests

Question 44

What is completely randomized design (two factor)?

Answer 44

the effects of two factors are tested at the same time | saves time and expense