Important Characteristics of Data

     1.  The shape of the distribution  ... mound, even, skewed
 

     2.  A representative value -  measure of middle  (average)
 

     3.  Measure of spread or scattering or variation
 
 

  Again - values meaningless if improperly collected
 

SUMMARIZING DATA
     *  Lose specific values because later are all treated as being in the middle

     Frequency Table   #4
 

Weight (kg)	Frequency	Relative Frequency	Cumulative Frequency
0.0-4.9	60
5.0-9.9	58
10.0-14.9	61
15.0-19.9	62
20.0-24.9	59

 

     Lower ( & upper) Class LIMITS
 
 

     Class BOUNDARIES

     Class MARKS - Midpoint of Classes

     Class WIDTH - difference between 2 consecutive lower class limits
 
 

Construct a table          *rules  bottom pg. 40 to top 41

     1)  Determine # of classes   5 to 20

     2)  Class width = (range/ # classes)  rounded up to convenient number

     3)  Select lower limits    (lowest score or convenient value lower)

     4)  Add class width to get next lower limits

     5)  Find upper limits
 
     Do #16
 
 
 
 
 
 

Relative Frequency -  Do on table from problem 4 above ...
 
 
 

Cumulative Frequency - Do on table from problem ...