presentation of quantitative data Flashcards
summarising data in a table
summary table
standard practitice too include a summary paragraphs beneath a table explaining the numbers and drawing conclusions
bar charts
can be represented visually using a silo table graphical display so the difference in mean values can be easily seen
used when data is divided into categories (discrete data)
histograms
bars touch each other which shows that the x-axis data is continuous rather than discrete
x axis is made up of equal sized intervals of a single category
y axis represents the frewucney within each interval
scattergrams
do not depict differences but associations between co-variables
normal distribution
if you measure certain variables such as the height of all people in the school the freuquency of these measurements should form a bell-shaped curve - normal distribution which is symmetrical
within normal distribution most people are located in the middle area of the curve with very few people at the extreme ends
th mean median and mode all occupy the same midpoint of the curve which extends outwards and never tick the horizontal x axis
skewed distributions
some data sets derived from psychological scales or measurements may produce skewed distributions that is distributions that appear to lean to one side
a positive skew is where most of the distribution is concentrated towards the left of the graph resulting in a long tail on the right
example - very difficult test in which most pepe got low marks and only a handful at the higher end
mode - remains the at the highest point of thr peak
meadian comes next
mean is dragged across towards the tail
high scoring candidates have had the effect og pulling thr mensa to the right
negative skew is opposite
very easy test would produce a distribution where the bulk of the scores are concentrated on the right resulting in a tail on the left
mean is pulled dot the left this time
