EBVM

Question 1

this is when ALL animals in a population are examined to find something out about the population

Answer 1

Census

Question 2

this is when SOME of the animals in a population are examined to find something out about the population

Answer 2

sample survey

Question 3

this refers to the entire group of interest in a survey (‘all cows in UK’)

Answer 3

target population

Question 4

this refers to the animals we can (if we wish) include in a survey

Answer 4

study population

Question 5

this refers to the ‘thing’ we are surveying

Answer 5

sampling unit

Question 6

this is the list of all the animals in a study population

Answer 6

sampling frame

Question 7

this is a sample where we choose which individuals to include

Answer 7

non-probability sampling

Question 8

this is when we choose individuals for a survey because it is convenient (biased - not a goof representation of the population)

Answer 8

convenience sampling

Question 9

this is when we choose individuals for a survey, but try to represent the population (good theory but still biased)

Answer 9

purposive sampling

Question 10

this gives a deliberately unbiased and random sample

Answer 10

purposive sampling

Question 11

this is when a sampling frame is made and a random subset is selected

Answer 11

simple random sampling

Question 12

this is when there is no list of all individuals in a sampling frame available, so you create clusters, randomly select some clusters, then create a list of animals in the cluster and randomly sample some of them (less precise)

Answer 12

cluster sampling

Question 13

this is when characteristics of a population that might be important are identified, then random samples are taken from the groups with the characteristic in proportion to their occurrence in the population (more precise)

Answer 13

stratified sampling

Question 14

this refers to the ability of a survey to detect effects/relationships present

Answer 14

power

Question 15

this is a range of values within which we are confident that the true population value lies (usual at a 95% level)

Answer 15

confidence interval

Question 16

the sample size required for surveys demonstrating disease freedom depends on this

Answer 16

endemic prevalence

Question 17

this scale of measurement is unordered categories (eye color, sex, religion, etc)

Answer 17

nominal

Question 18

this scale of measurement is ordered categories (small -> medium -> large)

Answer 18

ordinal

Question 19

this scale of measurement is counts of things, round numbers only

Answer 19

discrete

Question 20

this scale of measurement is a numerical scale, fractions are allowed

Answer 20

continuous

Question 21

this type of continuous data is where 0 is arbitrary (temp - 0C is 32F)

Answer 21

interval data

Question 22

this type of continuous data is where 0 means nothing/none (weight)

Answer 22

ratio data

Question 23

this is the chance of seeing the effect we saw in trial data if the null hypothesis was true

Answer 23

p-value

Question 24

if the p-value is – the null must —

Answer 24

low, go

Question 25

this type of error is when we conclude there is a difference when there is not one (reject a true null hypothesis)

Answer 25

type 1 error

Question 26

this type of error is when we fail to spot a difference that is really there (fail to reject a false null hypothesis)

Answer 26

type 2 error

Question 27

sample size and power of a study are (negatively or positively?) correlated

Answer 27

positively (bigger sample size = higher power)

Question 28

effect size and power of a study are (negatively or positively?) correlated

Answer 28

positively (bigger effect = greater power)

Question 29

individual variation and power of a study are (negatively or positively?) correlated

Answer 29

negatively (more indiv variation = less power)

Question 30

this type of study does not change anything in the animals they study; rely on variation in treatment and risk factor exposures that occur naturally

Answer 30

observational study

Question 31

this type of observational study is when a random sample of animals is taken at one time simultaneously assessing exposure to risk factor so prevalence of disease can be estimated in each group

Answer 31

cross-sectional study

Question 32

if the prevalence ratio = 1, this suggests ...

Answer 32

no association of disease occurrence with risk factor

Question 33

if the prevalence ratio < 1, this suggests...

Answer 33

animals w/ exposure to risk factor are less likely to have disease

Question 34

if the prevalence ratio > 1, this suggests ...

Answer 34

animals w/ exposure to risk factor are more likely to have disease

Question 35

this type of observational study classifies individuals from a random population sample into unexposed and exposed to a risk factor, then follows individuals over a period of time and records any developing disease

Answer 35

cohort study

Question 36

this is the measure of new cases of disease and can be estimated from cohort studies

Answer 36

incidence

Question 37

this is the proportion of healthy animals that become ill during the period of study in a cohort study

Answer 37

cumulative incidence

Question 38

this is the ratio of cumulative incidence in exposed group to control group

Answer 38

relative risk

Question 39

if relative risk > 1, this suggests...

Answer 39

exposure is associated with increased disease risk

Question 40

if relative risk < 1, this suggests...

Answer 40

exposure is associated with decreased disease risk

Question 41

this type of observational study is for rare diseases and asks to be informed about cases if a disease, then presence/absence of a putative risk factor is compared

Answer 41

case-control study

Question 42

these tell us the strength of association between a risk factor and disease

Answer 42

measures of association (prevalence ratio, relative risk, odds ratio)

Question 43

this shows us the chance of seeing an association we observed between a risk factor and disease IF there is really no association (null hypothesis is true) - helps make sure we are not fooled by chance

Answer 43

statistical hypothesis test

Question 44

this is when 2+ risk factors together have a different effect of disease risk than what we would expect from knowledge of individual effects

Answer 44

interaction

Question 45

this is when the effects of exposure on a given outcome are mixed with effects if an additional factor resulting in distortion of true relationship

Answer 45

confounding

Question 46

this type of study is when we manipulate treatment of individuals to assess the efficacy of a treatment

Answer 46

clinical trial

Question 47

this type of clinical trial is when therapy is given to some animals and the outcomes are assessed

Answer 47

uncontrolled trial

Question 48

this type of clinical trial compares outcomes in a treated group with another group

Answer 48

controlled trial

Question 49

this type of controlled clinical trial compares the treatment group with parallel control group at same time

Answer 49

concurrent control group

Question 50

this type of controlled clinical trial compares treatment group with control group in past, possibly from another study

Answer 50

historic control group

Question 51

this type of control group is untreated

Answer 51

negative control

Question 52

this type of control group is given a known, effective treatment

Answer 52

positive control

Question 53

this type of control group is given a substance/therapy with no known therapeutic effect

Answer 53

placebo control

Question 54

this is when the patient/owner doesn't know which group they're in, done to prevent bias

Answer 54

single blinding

Question 55

this is when the patient/owner AND investigator/vet doesn't know which groups are which, done to prevent bias

Answer 55

double blinding

Question 56

this type of clinical trial compares treatment groups to a control group, quick and satisfactory

Answer 56

simple trial

Question 57

this type of clinical trial compares a treatment group to a control group for a period of time then swaps the groups, finer and more sensitive/powerful

Answer 57

cross-over trial

Question 58

this type of clinical trial randomly allocates patients to treatment or control group when they are identified with the disease then progress is monitored

Answer 58

sequential trial

Question 59

this is reported as the etiological fraction and is the prevalence reduction in vaccinated vs unvaccinated animals divided by the prevalence in unvaccinated animals

Answer 59

vaccinal efficacy

Question 60

this is reported as reduction in parasite numbers between untreated and treated animals divided by the parasite numbers in untreated animals

Answer 60

ectoparasite efficacy