correlations Flashcards
define correlations (1)
a mathematical technique in which a researcher investigates an association between 2 variables (covariables)
define covariables (2)
the two variables in a correlational study that are measured to see if there is a relationship between them.
they are not manipulated, just observed as they naturally occur.
define positive correlation
as one co-variable increases so does the other
give an example of positive correlation
the number of people in a room and noise are positively correlated
define negative correlation
as one co-variable increases the other decreases
give an example of negative correlation
number of people in a room and the amount of personal space is negatively correlated
define zero correlation
when there is no relationship between co-variables
give an example of zero correlation
the association between the number of people in a room in Manchester and the total daily rainfall in Peru
what does correlation illustrate ?
the strength and direction of an association between 2 or more co-variables
where are correlations plotted on ?
scattergram
what does one co-variable and the other form ?
the x-axis + the other the y-axis
how would an individual work out to see if the use of caffeine is correlated with high anxiety ? (3)
- may get people to work out how many caffeine drinks they consume over a weekly period
- then use the same people to self-report their level of anxiety (using a 20-point scale) at the end of the week
what may one expect to see between caffeine and high levels of anxiety ? (2)
- might expect to see a positive correlation
–> means more caffeine people drink the higher the level of anxiety
how would an individual work out to see if the use of caffeine is correlated with amount of sleep one has ?
- could use the same people to record how many hours of sleep they have over a week
- may get people to work out how many caffeine drinks they consume over a weekly period
what may one expect to see between caffeine and amount of sleep one has ?
- drinking a lot of caffeine disrupts sleep patterns
–> so perhaps more caffeine someone drinks the less sleep they have hence negative correlated
how could we find a result of no correlations with the variables above ? (3)
- the number of dogs one sees in the street within the same week
- there is no relationship between the number of dogs one sees in the street and the number of caffeine drinks one drinks
- expect to find something close to 0 correlation or exactly 0 correlation
what does the researcher do in experiments with the IV and why ?
controls and manipulates it –> in order to measure the effect on the DV
why is it possible to infer that the IV caused any observed changes in the DV ?
as a result of this deliberate change in one variable
if there is no manipulation of one variable in correlation it means … ?
it is not possible to establish cause and effect between one co-variable and another
give an example of the fact there is no manipulation in variable: (CAFFEINE) (3)
if one found a strong positive correlation between caffeine and anxiety level we cannot assume that caffeine was the cause of anxiety
–> people may be anxious for all sorts of reasons (stressful job , personality type)
define intervening variables (3)
factors that come between the independent variable (IV) and the dependent variable (DV) in an experiment and explain how or why the IV affects the DV. They are not directly measured but influence the outcome
give an example of intervening variables
if higher income (IV) leads to better health (DV), an intervening variable could be access to healthier food
draw a positive correlation labelled correctly and without the coefficient
+ 1 and look in textbook :)
draw a negative correlation labelled correctly and without the coefficient
-1 and look in textbook :)