Session 5

Question 1

What is a ‘population’?

Answer 1

the large group of ALL possible scores that would be obtained IF the behavior of every individual of interest in a particular situation could be measured

Question 2

What is a ‘sample’?

Answer 2

A relatively small subset of a population that is selected to represent or stand in for the population; a subset of the complete group of scores found in any particular situation

Question 3

The __________________ is everybody you are interested in learning about.

Answer 3

population

Question 4

What is a census?

Answer 4

gives an accurate demographic of a population

Question 5

A _____________ is subset of population and stand for and represents the population of interest.

Answer 5

sample

Question 6

What is the link between sample and population?

Answer 6

Inference

Question 7

What is inference?

Answer 7

researchers infer that the characteristics of the sample probably are the characteristics of the population

Question 8

Inferences must have ______________ ____________, setting limits on the possibility that we are wrong. 1% or 5%

Answer 8

statistical significance

Question 9

What are the two questions researchers ask when evaluating a sample?

Answer 9

1. Is the size adequate?

2. Is the sample biased?

Question 10

What makes a sample unbiased?

Answer 10

random samples in which every member of the population of interest have an equal and independent chance of being included int he sample

Question 11

What is another name for random sample?

Answer 11

simple random sample

Question 12

What is the biggest task of sampling?

Answer 12

defining the population as specifically as possible

Question 13

What is a bias free sample called?

Answer 13

Simple random sample

Question 14

Can a bias free sample contain error?

Answer 14

yes, but it is still bias free

Question 15

What is potentially biased but easier way to approach sampling?

Answer 15

volunteerism

Question 16

Describe two ways of volunteerism recruitment?

Answer 16

1. researchers issue a call for volunteers

2. researchers identify a random sample from a population, but only certain people choose to participate

Question 17

Why is volunteerism a source of bias?

Answer 17

because those who volunteer may be fundamentally different from non-volunteers

Question 18

What are the two types of errors that random samples are subject to?

Answer 18

1. Sampling Error

2. Systematic Error

Question 19

What is sampling error?

Answer 19

the difference, due to random choice, between a sample statistic and the population parameter it represents

Question 20

What is Systematic error?

Answer 20

the difference, due to non chance errors, between a sample statistic and the population parameter it represents

Question 21

Is a sample EVER perfect?

Answer 21

1. there will never be a perfect representation of population.
2. there will always be sampling error

Question 22

Sampling error is created by_______ ___________.

Answer 22

random chance

Question 23

Sampling Error is reduced by ___________________.

Answer 23

adequate sample size

Question 24

Sampling error is evaluated with ________________.

Answer 24

inferential statistics

Question 25

Systematic Error is created by ______________.

Answer 25

bias in sampling

Question 26

Systematic error is reduced by _______________.

Answer 26

using sampling methods that are less subject to bias

Question 27

Systematic error is evaluated with ________.

Answer 27

review of sampling methods used for possible sources of bias

Question 28

Why is systematic error worse than sampling error?

Answer 28

random chance errors can be cancelled out by the introduction of another subject however systematic is throughout and full of bias

Question 29

What is systematic sampling?

Answer 29

every nth participant is selected from a list of the members of the population

Question 30

What is the source of bias in systematic sampling?

Answer 30

list of the population may be ordered in such a way that every nth participant is fundamentally different from every non-nth participant

Question 31

What is precision in sampling?

Answer 31

the magnitude of sample errors

Question 32

Precision is increased by _______.

Answer 32

reducing sampling errors through

Question 33

List two ways to reduce sampling errors.

Answer 33

1. increase sample size | 2. stratified random sampling

Question 34

What is the most efficient sampling method?

Answer 34

SRS: stratified random sampling

Question 35

What is stratified random sampling?

Answer 35

the most efficient method of sampling

Question 36

List the 2 steps of stratified random sampling.

Answer 36

1. identification of important subgroups (strata) in the population 2. proportionate random selection of participants from each subgroup

Question 37

What is the source of bias in stratified random sampling?

Answer 37

stratification not based on a variable that is relevant to the issue being studied

Question 38

In stratified random sampling, the sample preserves the same ___________ as the entire population.

Answer 38

proportion

Question 39

Stratified random sampling uses a number of ____________ __________.

Answer 39

stratification variables

Question 40

What approach improves precision in stratified random sampling?

Answer 40

using multiple strata (multiple variables for stratification) in selecting a given sample.

Question 41

Use of multiple strata improves precision as long as (2) ________, __________.

Answer 41

1. variables chosen are relevant | 2. variables chosen are indecent (unrelated) to each other

Question 42

What is independence?

Answer 42

one thing not affecting the other

Question 43

What is the primary purpose of Stratification?

Answer 43

1. to ensure that different subgroups are represented in the correct PROPORTIONS. 2. NOT to make comparison across subgroups 3. But to obtain a single sample that is representative in terms of the stratification variable

Question 44

What is cluster Sampling?

Answer 44

certain groups are randomly selected and ALL participants in each group are observed

Question 45

What is the source of bias in Cluster Sampling?

Answer 45

1. clusters not drawn at random | 2. each cluster tends to be more homogeneous in a variety of ways than the population as a whole.

Question 46

What is Purposive Sampling?

Answer 46

select individuals whom researcher believes will be good source of information

Question 47

What is the source of bias in purposive sampling?

Answer 47

researcher bias

Question 48

Qualitative research primarily uses what type of sampling?

Answer 48

purposive

Question 49

In Purposive sampling the ________________ has selected this population and therefore introduced their own bias.

Answer 49

researcher

Question 50

What is Snowball Sampling?

Answer 50

researcher contacts potential participants who have been identified by previously tested participants

Question 51

What is demographics?

Answer 51

the background characteristics of the participants in research

Question 52

List 3 things that demographics are used for

Answer 52

1. provide a picture of the types of individuals who constitute the sample 2. Analyzing and interpreting the results of the study 3. allow readers to make informed judgments regarding the extent to which the results may apply to their own setting

Question 53

What is Mortality Bias?

Answer 53

participants who drop out of the experiment at some point may be different fro those who remain or the population in general

Question 54

What 3 things should be reported in mortality bias?

Answer 54

1. if mortality occurred 2. number and percentage who dropped out from each group 3. demographics of those who dropped out and those who completed the experiment

Question 55

Precision is increased by what two factors?

Answer 55

1. increasing sample size | 2. stratified random sampling

Question 56

Precision is obtained by what 2 factors?

Answer 56

1. striving for an unbiased sample | 2. seeking a reasonably large number of participants

Question 57

List 3 reasons why TOO large a sample is not good.

Answer 57

1. principle of diminishing returns 2. with larger samples, the possibility of researcher error increases 3 with larger samples the possibility of supporting the research hypothesis when it is not true increases

Question 58

List 5 Major factors that influence researchers' decision on how large sample size should be.

Answer 58

1. pilot study 2. procedures expensive/time-consuming 3. documenting incidence of something rare 4. variability of population of interest 5. looking for small differences

Question 59

What are 3 details about pilot studies?

Answer 59

1. conducted to obtain preliminary info on how new treatments and instruments work 2. on the basis of the results, treatments and instruments are modified 3. smaller (10-100)

Question 60

If procedures are expensive and/or time-consuming what size sample would the researcher use?

Answer 60

smaller

Question 61

If documenting an incidence of something rare what size sample would be used?

Answer 61

larger

Question 62

If the population is homogeneous, what sample size is used?

Answer 62

smaller

Question 63

If the population is heterogeneous, what sample size is used?

Answer 63

larger

Question 64

If the researcher is looking for small differences, what sample size is used?

Answer 64

larger

Question 65

Why does a heterogeneous group require larger sample size?

Answer 65

in order to capture all the variety within the population

Question 66

What two factors determine whether to use a small or large sample size?

Answer 66

1. it depends on the size of the population of interest | 2. it depends on traditional sample sizes for this type of research

Question 67

researh

Answer 67

D