Non probability sampling researchers select people into the study by non random

Non probability sampling researchers select people

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Non-probability sampling: researchers select people into the study by non-random methods, and not everyone has the same chance to be included. o Convenience sampling: selecting the most conveniently available people as participants. Weakest form of sampling, risk of bias. o Quota sampling: researchers identify population strata and figure out how many people are needed from each stratum. o Consecutive sampling: recruiting all people from an accessible population over a specific time interval or for a specified sample size.
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o Purposive sampling: using researchers’ knowledge about the population to handpick sample members. Probability sampling: random selection of elements from a population. Each element has an equal, independent chance of being selected. o Simple random sampling: most basic probability sampling. Researchers establish a sampling frame. o Stratified random sampling: population is divided into 2 or more strata from which elements are randomly selected. o Systematic sampling: involves the selection of every x TH case from a list. Ex: every 10 TH person on the list is selected. Sample size: number of participants. Larger is usually better. Power analysis: researchers estimate how large their samples should be for testing hypotheses. Critiquing sampling plans: o Type of sampling approach used (convenience, consecutive, random) o Population and eligibility criteria from sample selection o Sample size, with a rationale o Description of the sample’s main characteristics (age, gender, clinical status, etc) Data collection in quantitative research Self-report data/ Patient-reported outcome (PRO): participants responses to researchers’ questions (ex: interview). Most common data collection approach in nursing. o Interview schedule: when questions are asked orally face-to-face or by telephone. o Open/closed ended questions. o Interviews vs questionnaires: Questionnaires = less costly, advantageous geographically, economical, autonomity. Interviews = response rates are higher when face-to-face, less likely to reuse to talk, feasible. o Scale: device that assigns a numeric score to people along a continuum Observational methods: used to gather information as patients’ conditions, verbal communication, non-verbal communication, activities, and environmental conditions. o Category system: records events of interest that happen within a setting systematically. Biophysiologic measures: Reliability: extent to which are free from measurement error. Test-retest reliability: replication takes the form of administering a measure to the same people on 2 occasions. Validity: the degree that an instrument is actually measuring the construct it supposes to measure. o Face validity: whether the instrument looks like it is measuring the target construct o Content validity: the extent that an instrument’s content adequately captures the construct o Criterion validity: extent to which the scores on a measure are a replication of a gold standard.
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