Analysing Descriptive Statistics!! Flashcards
What are descriptive statistics used for?
Descriptive Statistics organise / summarise a set of data.
E.G. percentages, measures of central tendency measures of dispersion & correlation coefficients
What are measures of central tendency and what are they used for?
-of a distribution of scores!!-
Measures of central tendency describe the typical, average and centre of a distribution of scores.
Mode = most frequently occurring score in a distribution. Median = midpoint of a distribution of scores. Mean = average of a distribution of scores
What are measures of dispersion and what are they used for?
M.O.D describe degree of spread in a set of scores! (Scores similar / clustered around mean / a lot of variability in scores?)
Range - measures distance between highest & lowest scores
Standard deviation = more sophisticated m.o.d. MEASURES THE AVERAGE DISTANCE OF SCORES FROM THE MEAN
The variance = the standard deviation squared. Also measures the distance of scores from the mean.
When are are means & standard deviations typically used?
for experimental research studies in which an IV was manipulated to produce two or more groups and a DV was measured quantitatively.
The means from each experimental group/condition are calculated separately, then compared to see if they differ
For non experimental research, what is typically used?
percentages may be used e.g. describe percentage of people who engaged in a behaviour
MORE LIKELY - calculating correlation coefficient between 2 variables
A correlation coefficient describes the strength & direction of the relationship between two variables.
Values of a correlation coefficient range from −1 (the strongest possible negative relationship) to +1 (the strongest possible positive relationship).
Value of 0 = no relationship between the variables.
Positive correlation coefficients - as the values of one variable increase, so do the values of the other variable.
e.g. correlation between height & weight.
Negative correlation coefficients - as the value of one variable increase, the values of the other variable decrease. E.G. negative correlation: correlation between stressful life events and happiness; as stress increases, happiness is likely to decrease
