research methods Flashcards
independent variable
some aspect of the experimental situation which is directly manipulated by the experiment to see id it causes a change in some other behaviour
dependent variable
Any change in performance that occurs after the independent variable has been applied is called the dependent variable
Sampling
Sampling is the he process by which research psychologists attempt to select a representative group from the population under study (target population)
why is sampling useful?
An entire population is too big to study, therefore a smaller group must act as a representative sample
what are the six sampling methods?
Random Sampling Stratified Sampling Quota Sampling Systematic Sampling Opportunity Sampling Self-selected Sampling Volunteer Sample
why do we need a representative sample?
because of how you need a sample that represents everyone
how would you pick a random sample out of 20 people
you would pick random names and use those people e.g using a computer program or pulled names out of a hat
why do a few studies actually use random sampling?
he advantages are that your sample should represent the target population and eliminate sampling bias
why do a few studies actually use random sampling?
the advantages are that your sample should represent the target population and eliminate sampling bias
why do some people not like random sampling?
because it is very time consuming since some people may not wish to be involved in the sample or may not be available or you may not want to pick someone because of their physical appearance etc
what are quantitive methods?
they are those which focus on numbers and frequencies rather than meaning and experience
quantitive methods such as experiments and questionnaires which is easy to analyse statistically and fairly reliable
what are qualitative methods?
methods are ways of collecting data which are concerned with describing meaning, rather than with drawing statistical inferences
What qualitative methods (e.g. case studies and interviews) lose on reliability they gain in terms of validity. They provide a more in depth and rich description
•There are 3 measures which give us an idea of the “central tendency” of data – a bit like the middle value, what are they?
- Mean (this is what most people call the average value)
- Mode (this is the value that occurs most frequently)
- Median (this is the middle value when all other values are placed in rank order)
There are 3 measures which give us an idea of the “central tendency” of data – a bit like the middle value, what are they?
- Mean (this is what most people call the average value)
- Mode (this is the value that occurs most frequently)
- Median (this is the middle value when all other values are placed in rank order)
what are measures of dispersion?
range
standard deviation
how is the mean calculated?
the mean is calculated by adding all the numbers together and dividing by the number of scores
why is the mean useful?
it is most useful score statistically as it includes all of the scores in its calculation and is the basis of other calculations such as the standard deviation.
how is the medium obtained?
the medium is found by putting scores in an order from low to high and then finding the one in the centre. if there is two numbers in the middle then the mean of the two scores is calculated.
why is the mode useful?
the mode is the most common score and although it is less useful statistically it is useful to know which score is actually most common
what does dispersion mean?
how widely the data is spread out
how is the range calculated?
the range is based on the difference between the lowest and highest scores. it is calculated by subtracting the lowest score from the highest.
what is a disadvantage of calculating the range?
it does not reflect the distribution of other data which can result in extreme scores
what is the interquartile range and how is it calculated?
listing numerical data in order from lowest to highest and then finding difference between the scores at the 25% and 75% points, that is, the difference between score one quarter from the bottom of the top. distribution and the score one-quarter from the bottom of the distribution and the score one quarter from the top. it is an easy way to avoid extreme scores
what is the interquartile range and how is it calculated?
listing numerical data in order from lowest to highest and then finding difference between the scores at the 25% and 75% points, that is, the difference between score one quarter from the bottom of the top. distribution and the score one-quarter from the bottom of the distribution and the score one quarter from the top.
what is a limitation of using the mode?
it relies on there being at least one score which is shown more than once in the data
what is a disadvantage of using the medium?
Not as sensitive as the mean because not all values are reflected in the median
what is a disadvantage of using the median?
Not as sensitive as the mean because not all values are reflected in the median
what is good about using the median?
it is an easy way to avoid extreme scores
