Week 3: Research Questions, And Sampling Flashcards
Variables
What are the two types of variables and explain them?
Independent variable:
-a condition, intervention or characteristic that will predict or cause a given outcome
-something that is manipulated by the researcher
Has 2 or more levels: groups or conditions to be explored
Eg a study comparing the effectiveness of spinal manipulation versus a walking program got patients with low back pain
Dependant variable:
-a response of effect that is presumed to vary depending on the independent variable
-“outcome variable”
Eg level of low back pain
Variable definition
Operational definition
Conceptual definition
Conceptual definition:
- dictionary definition
- eg low back pain= level of discomfort in the back
Operational definition:
-defines a variable according to its unique meaning in the study
Independent variable: defines a variable according to its unique meaning in the study eg walking program= 10 weeks of daily walking sessions of 60 minutes
Dependant variable: is operationally defined by describing the details related to the method of measurement eg
Low back pain= low back pain intensity as measured on the numeric pain rating scale as measured at the margining of each treatment session.
Research objectives
Research objectives:
-provide clarification for the objectives of the study
-specific, concise, delineate what is to be accomplished
-include the variables and population studied
Stated in the form of:
-specific aims
-purpose statement
-research objectives
Often include hypothesis found at the end of the introduction
What are the 4 types of research objectives?
- Comparing for differences
- Exploring relationships eg video game use and obesity
- Describing phenomenon
- Examining measurement issues
- Comparing for differences:
“We will examine for differences in pain intensity among patients with low back pain who will be randomised to receive either spinal manipulative therapy of exercise.”
- Exploring for relationships:
“We will seek to identify the level of correlation between video game use and body mass index.”
- Describing phenomenon
“We will describe the types of musculoskeletal health complaints often encountered by exercise physiologist practicing in a rural health setting.”
- Examining measurement issues:
“We will examine the validity of motion palpating by comparing the manual assessment of joint motion with videofluoscopy.”
Measurement in this case refers to measurement properties such as reliability, validity, and responsiveness
Hypotheses
Can be directional or non directional
Statistical hypothesis
Research hypothesis
Can be directional or non directional
-states the researchers expectation of results
-directional or non directional
Nondirectional: “there will be a difference in perceived learning between students enrolled in online or on-campus courses”
Directional: “students enrolled in on-campus courses will exhibit higher levels of perceived learning as compared to students enrolled in online courses” (shows direction of change)
Statistical hypothesis ie null hypothesis
“There will be no difference in perceived learning between students enrolled in online classes and those enrolled in on-campus courses.”
What is a population?
-persons, objects or events that meet a specific set of criteria
Target population: the larger population to which results of a study will be generalised to.
Accessible population: the actual population of subjects available to be chosen for a study (a subset of the target population)
What is a Sample?
Give an example of population and sample
A subgroup of the population of interest which allows the results of research to be ‘generalised’ to the population.
Eg: study of sports scientists attitudes about rehab following hamstring injury.
Target population: sports scientist practicing in Australia
Accessible population: active members of exercise and sports science Australia
Sample: sports scientists chosen at random who answers a survey
What is sampling bias?
Conscious sampling bias?
Unconscious sampling bias?
Sampling bias is when individuals in a sample do not represent the attributes of the population
Conscious SB: when a sample is purposely selected
Eg testing a weight loss pill among individuals starting weight watchers
Unconscious SB: researchers own bias affects recruitment of subjects eg researcher approaches individuals who appear friendly
What is sampling error?
The difference between sample statistics and population parameters
Eg mean activity level for
Individuals in the target population: 45mins of exercise/week
Individuals in sample = 145 mins exercise/week
Sampling error = 100 mins
Sampling techniques
What is probability sampling?
What is non-probability sampling?
Probability sampling: (AKA random sampling)
-a process of random selection in which each individual in a population has an equal chance of being selected
-helps to eliminate bias
-sample is considered to represent the population
Non-probability sampling:
-selection of participants is by non-random methods
-may be biased regarding age, severity of the condition, socioeconomic status etc
-sample is not considered to represent the population
Probability sampling
Simple random sampling?
- draws a random sample from an accessible population
- often accomplished with a table of random numbers or computers generated lists of numbers
