Research Methods Flashcards
Hypothesis
A precise, testable statement about the predicted outcome of the investigation
Directional hypothesis (one tailed)
A prediction which states the direction between two conditions
Non directional hypothesis (two tailed)
A prediction which states that there will be a difference between conditions or that there will be a correlation but which doesn’t state the direction the difference will go in
Extraneous variables
Any variable which may affect the dependent variable other than the IV
Confounding variable
One which affects the dependent variable and which varies systematically with the independent variable
Independent groups
Different participants in each condition of the independent variable
Repeated measures
Each participant does both conditions of the independent variable
Matched pairs
Each person only does one condition of the independent variable but they are matched with another person doing the other condition on some extraneous variable
Counterbalancing in repeated measures
Half the participants do conditions in one particular order and the other half do the condition in the opposite order
This is done to balance possible order effects
Advantages and disadvantages of independent groups
No chance of practise effects between the first time and second time
No chance of participants becoming bored
Participant variables
Advantages and disadvantages of repeated measures
Controls for differences between people
Requires fewer participants
There may be order effects
Boredom
Practise
Lab experimental method
Conducted in a controlled environment
Fired experimental method
Conducted in a real world environment
Natural experiment
The independent variable has not been manipulated by the experimenter but it has changed or occurred naturally
Eg Romanian orphanages
Quasi experiment
The independent variable is not manipulated
Eg investigating differences between men and women on a certain variable
Quantitative data
Information that is gathered that is in numerical form
Negatively skewed distribution
The curve leans over to the right
The mean is less than the median and the mode
Mean, median,mode
Eg test too easy (more students getting high scores)
Positively skewed distribution
Curve leans overs to the left
The mean is more than the median and mode
Mode, median, mean
Eg test too hard
Name the measures of central tendency
Mean
Median
Mode
Name the measures of dispersion
Standard deviation
Interquartile range
Range
Standard deviation
The average about that the scores differ from the mean
The larger the standard deviation, the more the data is spread out
Tells us how consistent people’s scores were
Advantages and disadvantages of standard deviation
Much less affected by outliers compared to the range
Much more sensitive measure of dispersion compared to the range as it uses all the data from the sample in its calculation
Much more difficult to interpret
Name the levels of measurement
Nominal
Ordinal
Interval
Levels of measurement- nominal
Categories
Levels of measurement- ordinal
Rank order
Levels of measurement- interval level
Precise intervals
Safe and unsafe interval scales
Safe- each unit on the scale is exactly the same (eg tape measure)
Unsafe- not directly observable eg depression
We can’t be sure that the distance between each interval is always exactly the same
When to use the sign test
When the DV has been organised into categories (nominal)
When it is a repeated measures of matched pairs design
When we are testing for a difference between conditions
In the sign test, when is the result significant?
If our observed value is equal to or less than the critical value
What does it mean if a result is significant?
It means that is is very unlikely to have occurred by chance
Type one error
You mistakenly conclude that there is an effect when it was just coincidence
To recede the possibility of a type 1 error: choose a stricter level or significance, repeat the study