Modlue 2 chpt 13,14,16

Question 1

representative sample

Answer 1

characteristics of the sample should match the characteristics of the condition (ie if a condition is seen more often in males, your study population should have a larger male population) - will affect the validity

Question 2

sample size

Answer 2

larger the size the better

Question 3

probability sampling

Answer 3

random selection alues)of elements

• best method for ampling
• can estimate the magnitude of sampling error (diff btw sampling valuses and population values)
• impractical

Question 4

nonprobability sampling

Answer 4

non-random methods

• rarely representative of the popultaion
• more practical
• convience the worst
• quota better

Question 5

convenience sampling

Answer 5

NON-probability
most available people - placing an ad - respondents are those with the condition, using people from a location where the characteristic is saturated

may not be representative of the population

Question 6

snowball sampling

Answer 6

NON-probability

- network, chain - one refers another

Question 7

quota sampling

Answer 7

NON-probability
determine how many are needed in the study, recruit and stop at that number. Works for those where convenience sampling might result in a lack of balance - ie male vs female

Question 8

consecutive sampling

Answer 8

NON-probability
recruiting all people from an accessible population who meet eligibility criteria over a specified time for a specified sample size. “x type of patients in a 6 moth period” or “x type of patient until 250 patients are enrolled”
better than convience
good for rolling enrollment

Question 9

purposive sampling

Answer 9

NON-probability
uses researchers knowledge about the population to make selections
eg Delphi survey
BUT - may not result in a typical or representative sample
good for two-stage sampling (select a site using purposeful sampling then use random sampling within the site)

Question 10

simple random sampling

Answer 10

probability
establish a sample frame, elements numbered, use random number or softwear to select the included participants
- laborous, possibly non represetativeness (but decresases as size increases), inefficient
-unbiased

Question 11

stratified random sampling

Answer 11

probability
divided into 2+ homogeneous strata (eg gender)
-status must be known prior to selection
porportionate stratification - selections from the starta are balanced to match population - used weighting to balance put population

Question 12

cluster sampling

Answer 12

probability
selecting broad groups first
select a sample of nursing schools from all nursing schools, then choose a sample of students from each school
-LESS accurate than simple or stratified, but more practical

Question 13

systematic sampling

Answer 13

probability

selecting every kth case from a list starting at a random number until the desired sample size is reached.