Scientific Processes Flashcards
Aim v hypothesis
What you intent to do vs predictions about what the researcher expects to find
Directional hypothesis
Stay the specific direction the research expects results to move in e.g. higher, lower, more, less
Nondirectional hypothesis
These state a difference will be found between the conditions of the independent variable but does not state the direction of the results
Random sampling
Everyone in the population has an equal chance of being selected
+ Fair, even chances
- Difficult to organise, usually results in small sample that’s unrepresentative 
Systematic sampling
every nth member of the target population would be selected e.g. every fifth pupil from the register
Systematic sampling advantage and limitation
+ evenly spread sample over population, unbiased
- Time and effort, complete list of population required, Random sampling less time consuming
Stratified sampling
P selected according to their frequency in the target population
Subgroups (strata) identified (e.g. gender, age)
Stratified sampling limitation an advantage
+ Representative, characteristics of target population are represented, more generalisable
- can be very time-consuming as the categories have to be identified and calculated.
Opportunity sampling
Uses people from target population available at the time
+ easiest, most convenient method
- unrepresentative of target population as it’s drawn from a specific area, makes it difficult to generalise findings
Volunteer sample with
advantages and disadvantages
Participant select themselves, for example by answering an advert
+ participants are likely to be more motivated and not dropout as they selected themselves (lower attrition rates)
- biased sample, P may share certain traits (e.g. keen, curious) generalisation limited due to volunteer bias
Pilot study
- Smaller version of the study carried out before the main research.
- aim: to identify any flaws in the study and carry out the necessary modifications before doing the full-scale study. (e.g ambiguous questions, errors)
Independent groups design with disadvantage
Participants take part in one condition
- individual differences between groups, making the groups different to begin with (extraneous/confounding variables)
Independent groups design advantages
+ No order effects as participants only take part in 1 condition, they do not get any practice between conditions. so there are no practice or fatigue effects.
+ less demand characteristics, less likely to guess the aim of the study as they’re only taking part in one condition
Repeated measures design and advantage
Participants take part in all conditions

+ No individual differences, as participants in each condition are the same
+ half the number of P needed for IG design, less time spent gathering a sample
Repeated measures design disadvantages
- order effects, if participants take part in both conditions, they may improve due to practise or perform worse due to boredom or fatigue.
- Demand characteristics, more likely to guess the aim of the research if they take part in both conditions
Matched pairs design with
disadvantage
Participants matched on variables which are considered to be relevant to the experiment in question
- matching is time consuming, and not perfect as you cannot control all relevant variables
- More P needed (2x more than RM) more time-consuming gathering sample
Matched pairs design advantages
- unlike IG design there is no individual differences between groups as they have been matched to their conditions
- no order effects (fatigue or practise) as only tested once
Event sampling
A target behaviour / event is recorded every time it occurs
+ May record infrequent behaviour that would be missed using time sampling
- Complex behaviour oversimplified, if the event is to complex details may go unrecorded
Time sampling
Observations made at regular intervals
+ reduces number of observations
(More structured and systematic)
- May be unrepresentative (missing out important details outside the time scale)
Independent variable
Whatever is being manipulated in the experiment
Dependent variable
Where is being measured in the experiment
Dependent on the independent variable