Experimental designs Flashcards
define single blind
the ppt is not aware of which level of the IV they are placed in. This prevents the ppt being aware of what the experiment is about and helps prevent ‘screw you effect’.
define double blind
this is when the ppt and the researcher are not aware of what level the ppt is placed in during the experiment. This prevents any bias
define ppt sampling
Smaller proportion of ppts that represent the larger study number
how is a sample calculated?
it depends on the amount of people that is in the total population, eg <5% would be used for a population of 20,000.
If you increase the sample size what happens to the representation of data? vice versa with if you decrease it.
The bigger the sample, more representative.
The smaller the sample, the less representative.
What are the five types of sampling?
random - number generator etc
opportunity - sampling wherever and taking the opportunity to do so.
volunteer - somebody voluntarily entering for the sample.
stratified - subgroups ‘strata’
systematic - at every regular interval
define aim of the experiment
the general intention of the study and what you’ll study in it.
define hypotheses
a prediction of what you thin/ expect to happen in an experiment
It predicts the expected influence of the change in the IV on the DV
Define operationalise
When you include units with a DV/ IV
what are the four steps to writing a hypothesis?
-identify the research aim + type of study
-identify exactly what is being manipulated (IV, categories, co-variables)
-identify the specific measure that will be taken (DV or covariable)
-identify if the hypothesis should be directional or non directional
what is the point of a experiment?
in these you are looking for a difference
what is the point of a correlation?
in these you are looking for a relationship
what are the two types of hypotheses?
directional
non-directional
what are directional hypotheses?
these are used when there is previous research indicating the likely difference you will find. These allow you to used a ‘one tailed test’
what are non directional hypotheses?
these are used when there isn’t previous research indicating the likely difference you will find. You have to use a ‘two tailed test’.
What is the point to operationalising?
it allows for other researchers to know exactly what has been changed and what has been measured.
How is something measured which is ‘intangible’?
the most common methods involve using a scale or statement with several options, e.g ‘how angry are you’?
define likert side
this includes several options e.g SA, A, N, D, SD
When it is a directional experiment/ correlation, do you write about the DV or IV first?
DV
when it is a non directional experiment/ correlation, do you write about the DV or the IV first?
IV
Define Null hypotheses
instead of making a prediction of what will be found in the experiment, the null hypothesis will state that there will be nothing found in the research.
what are the two reasons as to why a null hypothesis is used by a researcher?
it covers the probability that the hypothesis is incorrect
it helps the researcher to stay objective by adding extra distance between themselves and the experimental hypothesis.
what is difference between objectivity and subjectivity?
objectivity- unbiased study
subjectivity- biased study
what is the difficulty with experiments?
it is more likely to say that you have found nothing rather than finding something new, therefore the results aren’t published for old results and only is for anything new.
define correlational hypotheses
these look for a relationship instead of a difference. They predict there will be some form of relationship between the two covariables- usually starts with ‘ there will be a relationship between..’
What must you include if it is a directional correlational hypothesis?
Use either positive or negative to describe the type of hypothesis
define chi square statistical test
a test of association or difference and compares distant categories.
give an example of a chi square statistical test
e.g there will be an association or difference between birth order ( first of second) and career choice (academic or vocational).
