Displaying Grouped Data

Grouped?

When the data gets bunched together (normally because theres a bigger range which makes analysis easier)

grouped

ungrouped

This is a frequency distribution table for grouped data

This is a frequency distribution table for grouped data

Note that the “score” column has changed to the “class” column now

The “class centre” is the middle of the class

Class Intervals

Its all about splitting up your data

Its all about splitting up your data

in a way to avoid bias or skew

Its all about splitting up your data

in a way to avoid bias or skew

this usually means

Its all about splitting up your data

in a way to avoid bias or skew

this usually means

picking your classes so that they have an equal number of scores in them (broken up evenly)

H i s t o g r a m s a n d P o l y g o n s

H i s t o g r a m s a n d P o l y g o n s

Exactly the same as normal histograms and polygons

Except the class centre goes on the bottom of the column

Whassup?