research methods Flashcards
negative skew
the mean is on the left side of the median and mode so the tail is on the left.
this shows that a large amount of data falls above the mean score
positive skew
the mean is on the right side of the median and mode therefore the tail end is at the right side.
this shows that a large amount of data falls below the mean score.
skewed distributions
scores are clustered to one side of the mean.
distribution curves
(plot the frequency)
data can be distributed in different ways, either normal distributions or skewed distributions.
normal distribution
displays frequency data in a symmetrical bell shape pattern.
the mean ,median and mode are all located at the highest peak and the dispersion of scores around both sides of the average is consistent and expressed In standard deviation.
why do the tail end on normal distributions never touch the x axis
because extreme scores are always theoretically possible.
pie charts
used with discrete data.
each segment of circle represents a proportion of scores.
line graphs
also illustrate continuous data and use points connected by lines to show how something changes in value.
dv is plotted on y axis and iv plotted on x axis
histograms
illustrate the distribution /frequency of data items -continuous scores.
frequency on y axis and equal size intervals on x axis.
scattergram
used to show a relationship between two variables.
one co variable on x axis, one co variable on the y axis
a line of best fit may be drawn to estsblish the strength of relationship.
bar chart
used to make comparisons between scores and are used with different groups /categories of data (discrete data)
graphs
provide visual representation of a set of data that allows us to see the patterns in an east to understand way
tables
show a summary of the raw scoresconvverted to descriptive statistics.
small standard deviation
data points tend to be close to the mean pot the set
large standard deviation
data points are spread out over wider range of values
positive of standard deviation
sensitive and precise measure of dispersion as all values are take into consideration when calculating it.
negative of standard deviation
doesn’t tell you full range of the data and it can be affected by extreme scores to give a skewed picture
standard deviation defiition
statistical measure of variation in a set of data and describe how much, on average, all values differ from the mean.
range
the difference between the highest and lowest values
positive of range
easiest measure of dispersion to calculate
negative of range
only takes into account most extreme scores which makes it unrepresentative of the data set as a whole.
measures of dispersion
range - basic measure
standard deviation-sensitive measure
advantages of the mode
easiest measure to calculate and unnfacected by extreme values
its the only measure you could calculate when data is in categories eg nominal.
negative of mode
crude measure and can be unrepresentative in small data sets
becomes less useful when there are several modes in a data set
what’s the mode
value that occurs most often. can be used with all levels of measurement.
positive of the median
the median is not affected by extreme values and is therefore unuseful when the mean is not appropriate
easier to calculate than the mean
negative of the median
not as sensitive as the mean because it does not include all of the data scores or values in the set.
what’s a median
the central halfway value
asending order
positives of the mean
most sensitive measure of central tendency as it includes all of the scores in the data set and is therefore the most representative measure
negatives of mean
easily distorted by extreme values which may make it unrepresentative of the data set overall
mean definition
statistical average of a set of data.
measures of central tendencies
mean mode and median
descriptive data types
measure of central tendencies- info about the typical value
measures of dispersion - info about how spread out the values are
levels of measurement
nominal-attributes only named (WEAKEST)
ordinal- attributes can be ordered
interval- distance is meaningful
nominal data
categorical (eye colour, marital status)
frequency count for distinct categories where something can only belong to one separate category.
most basic and least informative data.
ordinal data-
categorical
numbers can be ordered in some way eg scale of 1-10 where 1- unattractive and 10- most attractive
interval data
scale- objective measure
measurements taken from a numerical scale where each unit is the same size and the gap between each unit is fixed and equal. eg length in cmheight
weight
time
income
positive of meta analysis
includes greater statistical power and more ability to generalise the findings to a wider population. considered to be evidenced based.
negative of meta analysis
meta analysis can be a difficult and time consuming in searching for the appropriate studies to examine.
meta analysis also require complex statistical skills and techniques.
what’s meta analysis
researcher combines the findings from a number of previously published studies dealing with the same research question and produces a statistic to represent an average and common overall effect.
secondary data
data thats collected bro there people and already exists.
primary data
collected by researcher first hand and gathered directly from participants themselves.
pros of primary data
AUTHENTIC as its collected first hand from the participants themselves and so is specifically targeted to meet researches needs
cons of primary data
TIME CONSUMING to collect investigations require planning and preparation
pros of secondary data
EASILY accessible and requires minimal effort to colleg=ct ads it already exists.
cons of secondary data
may not meet researchers NEEDS and could be lacking in valuable info or could be out of date.
quantitive data
numerical data
qualitative data
non numerical data
pros of quantitive data
OBJECTIVE -free from bias- and capable of being MATHEMATICALLY ANALYSED easily allowing comparisons to be made.
cons of quantitive data
fails to consider participants feelings and emotions and lacks insight into the reasons behind human behaviour.
pros of qualitative data
IN MORE DETAIL and broader scope, allowing people to develop thoughts.
data gives MEANINGFUL INSIGHT and therefore high in EXTERNAL VALIDITY.
cons of qualitative data
difficult to analyse statistically so that comparisons are hard to make.
conclusions are based on subjective interpretations.
disadvantages of correlations
only establish a relationship between variables.
variables aren’t being manipulated so we can’t state wether one variable has caused the effect on the other variable - there could be other extraneous variables that have an impact on the relationship.
therefore can’t establish cause and effect from correlational studies compared to the experimental method.
advantages of correlation
allow the study of variables which can’t be manipulated
this is bc correlation do not require manipulation of behaviour and are used used when it may be unethical and impractical to manipulate variables artificially in experiments.
therefore don’t break ethical guidelines.
advantages of correlations
useful in PRELIMINARY tool for further research.
as correlations are relatively quick and economical too conduct as they often use forms of secondary data. they can assess patterns of variables before as researcher commits to more length and time consuming research methods.
correlations can form the basis of a starting point for Reuther experimental research
correlation co efficient
more accurate way to indicate the strength of a correlation. always number between -1 and 1.
-1 being perfect neg and + one being perfect pos
how can correlations be shown
pictorially as a scattergram
numerically as a correlation coefficient