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