Grouped Frequency Distributions 19Nov09

1
Grouped Frequency Distributions 19-Nov-09
Understand the meaning of the following Class,
Class Width, Class Mid-Point, Lower Class Limit,
Upper Class Limit, Lower Class Boundary, Upper
Class Boundary, Frequency Polygon, Cumulative
Frequency Polygon.
2
Discrete Data 1, 4, 8, 8, 8, 9, 9, 9, 10, 10,
10, 11, 11, 11, 12, 12, 12, 12, 14, 14, 14, 14,
14, 15, 15, 15, 15, 16, 16, 16, 17, 17, 18, 18, 20
Classes
Aim to get between five and fifteen classes
Class Width (Largest - Smallest) Number of
Classes But use common sense i.e. (20 1) 5
3.8 ? 4
3
If we consider one class, the Class Mid-Point ?
(8 5) 2 6.5 Upper Class Limit ? 8 Lower
Class Limit ? 5 Upper Class Boundary ? 8.5 Lower
Class Boundary ? 4.5
You need to know and understand these terms
4
(No Transcript)
5
Frequency Polygon
6
Frequency Polygon
7
Data is grouped but only the upper class
boundary is tabulated. You must use this in
plotting
Cumulative Frequency Polygon
8
Put this data onto a grouped frequency table and
draw a frequency polygon of the data. 2, 2, 3,
4, 5, 5, 6, 6, 6, 7, 7, 8, 8, 9, 9,
10, 10, 10, 11, 11, 12, 12, 12, 12, 12,
13, 14, 16, 17, 20. Clearly mark the Class
Mid-Point, Upper Class Limit, Lower Class Limit,
Upper Class Boundary and Lower Class Boundary on
the frequency polygon
9
Mid Points Class Boundaries Class Limits