practical investigations things Flashcards
independent groups
define
Allocates participants randomly to be in either experimental or control group
independent groups
adventage and disadventage
A: completede quickly; withdrawl is low
D: requires large no of people to ensure participation vairance
matched participant design
define
pairing participants with similair characteristics, triat or qualities for what is being investigated
matched participant design
adventage and disadventage
A: result will not be influenced in unwanted way; E&C group results will be similiar
D: take a long time to find matching pair
repeated measures design
define
one participant is exposed to both E&C groups
repeated measures design
adventage and disadventage
A: less individual differences across groups
D: order effect can impact performance and have an unwanted effect on DV
sampling
Random sampling
define
Every member of population has an equal chance of being selected to be part of the study
random sampling
adventage and disadventage
A: results are often generalised to population - sample was a representative of pop. to begin with
D: requires a lot of time to randomly choose participants
random sampling
example
drawing names out of a hat, or computer generated names or number of participants/population
Stratified sampling
define
Dividing the population into specific sub-group and selecting participants from within each sub-group
stratified samplign
example
- take population of high school students (in a school)
- divide them into year levels (strata)
- choose a few students from each strata ACCORDING to what is being measured
- the few student from each strata are the new stratified sample
Random stratified sampling
defien
Same as stratified sampling but now randomly selecting participants in each strata
randomnly selecting from strata will ensure every participant have an equal chance of being selected for the study
Convenience sampling
define
participants are chosen based on their easy accessibilities and proximity to the researcher
convenience sampling
adventage and disadventage
A: Participants are easily accessible
D: Non-probability technique; result can’t be generalised to the population - wasnt a representation of population to start with
convenience sampling
example
Uni researchers might ask JUST for their students to volunteer to sign up to the study - if they are interessted
p-value of 0.02
p<0.05
the results are statistically significant and more likely to have occured due to the effect of the IV thus the results can be generalised to the wider population
p-value of 0.08
p>0.05
The p-value is not statisitcally significant and the experimental hypothesis cannnot be support thus the result cannot be generalised to the wider population
ethical principles
abrehviation
Perhaps Very Intelligetn Ducks Can Do Well
Protection & securtiy of participants rights
defien
esearchers must respect participants rights and needs to ensure their safety and well being is maintained
Voluntary participation
define
Participants chose to be involved in the study by their own free will - cannot not be pressured to sign up
Informed consent
defien
Participants must be provided with info prior to the study and told about th enature & purpose, any potential risks involved, their withdrawal rights and their consent to the study
Deception
defien
withholging particular info about the study - experimenter must ensure no significant distress or truama is caused and all participants must be debriefed about withheld info
if purpose of study is revealed - participants may act differently to how they normally would act
Confidentiality
define
must ensure all participants are not identifiable in any way - researchers cannot simply publish results in papers or on the internet
Debreifing
define
After the study is completed the participants must become aware of the results and conclusion of the study. This is where all misconceptions and withheld info is corrected and clarrified
Withdrawal rights
define
Give participants the right to leave the exerpiment at any given point and withdraw their results from the study too
alternative hypothesis
define
predicts that there is a relationship between the IV and DV
null hypothesis
define
precitds that there is no relationship between the IV and the DV
extraneous varibale
define
variables that need to be controlled to avoid influencing the DV
confounding cariables
define
Varibales that will influence the DV
e.g additional time to study or prior knowledge
types of validity
4 types
internal validity - is the result due to the IV
content validity - instrument measures what is says it does
construct validity - does the test support the theory
extneral validity - how natural is it /ecological validity
SD
define
finds the disperstion of individual data points from the mean - the larger the SD the grater dispersion/variation of points in the data
r-values
define
correlation coefficients (r) describes the relationship between two bariables
the closer to +1 or -1 the stornger the correlation, if closer to 0, there is no correlation
