Diagnostic Tests 3

Question 1

name 3 reasons to sample a population

Answer 1

determine health status of herd or group; detect presence of a pathogen; determine cause of morbidity/mortality/poor performance; for disease surveillance programs

Question 2

who is studied in a census? who is studied in a sample?

Answer 2

census samples the ENTIRE population. SAMPLE has subgroup of population selected to represent the entire population

Question 3

name a disadvantage of a CENSUS

Answer 3

expensive, labour intensive, usually not feasible

Question 4

name a disadvantage of a SAMPLE

Answer 4

prone to biases and error, especially if not chosen strategically

Question 5

describe type I (ALPHA) error

Answer 5

study concludes there is an association when in reality there is no association

Question 6

define type II (BETA) error

Answer 6

study concludes there is no association when in reality there is an association

Question 7

you conclude a herd is purple when in reality it is not purple. besides being colour-blind, what type of error did you commit

Answer 7

type II (BETA) error

Question 8

you divide your herd into groups then randomly select a certain number of animals per group to sample. what type of sampling are you using?

Answer 8

stratified random sampling

Question 9

you randomly select 5 animals out of a hat to sample. what type of sampling are you using?

Answer 9

random sampling

Question 10

you select every 5th cat to sample. what type of sampling are you using?

Answer 10

systematic random sampling