Skewed distributions
the long tail is to the left
describe a negative skew
all measures of central tendency lie together in the middle of the graph
describe a normal distribution
the long tail is to the right
describe a postive skew
where the pattern could have arisen by chance or due to the variables
what do statistical tests aim to do
the mean, median and mode are in different places
what is a consequence of skewed distributions
the single number calculated by a statistical test and is compared to a critical value
what is an observed value
the probability that a pattern in the results ave arisen by chance
what is significance level
a value taken from a table for the appropriate statistical test which is compared to the observed value
what is the critical value
the mean is the average, takes into account every score and uses the furthest along the tail
what is the mean and where is it located in skewed distributions
the median is the middle point, with 50% of scores either side, towards the end of the tail
what is the median and where is it located in skewed distributions
the mode is the most frequent and is the highest point of distribution
what is the mode and where is it located in skewed distributions
negative skew
what type of skew
normal distribution
what type of skew
postive skew
what type of skew
to make inferences about the data
why do we use inferential tests