Computer Shopper 125/Computer Shopper CD-ROM Issue 125 (1998-07)(Dennis Publishing).iso/EuroMath/MathDemo/DataBase/Help/ID612.TXT

Text File | 1996-08-28 | 3.8 KB | 192 lines

@atGraphic 15,1
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@at ,3
#<drawing histograms#



@animate PasPoint

@PlaySoundFile h1040101.wav





@at 100, 22
@definition
This section looks at how
to draw a histogram.
'@at 7,+4
'@keyPoint 9999,definition



@prompt
@At 10,51
@keyPoint 9999,the class


@PlaySoundFile h1040102.wav

#bclass#
The class is always shown on the horizontal
axis (x-axis).
@atgraphic 50,114
@picture datahand\h0401a.bmp




@prompt
@keyPoint 9999,the frequency density

@PlaySoundFile h1040103.wav

#bfrequency density#
#hFrequency density# is always shown on the
vertical axis (y-axis).

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@picture datahand\h0401b.bmp



@prompt
@keyPoint 9999,mid-point of class intervals

@PlaySoundFile h1040104.wav

#bmid-point of class intervals#
The mid-point of class intervals should be at the
centre of the column.
@atgraphic 49,113
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@prompt
@keyPoint 9999,upper and lower boundaries for discrete

@PlaySoundFile h1040105.wav

#bupper and lower boundaries#
The extremes of each column represent the
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upper or lower boundaries of each class.
'@at ,-1

@Wait 0.5
@PlaySoundFile h1040106.wav
So, if the data is discrete,  for the class 20-29:
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                    upper bound, or boundary  #^= 29
'@at ,-2
                    lower bound, or boundary  #t= 20
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@prompt
@keyPoint 9999,upper and lower boundaries for continuous
#bupper and lower boundaries#
The extremes of each column represent the
'@at ,-1
upper or lower boundaries of each class.
'@at ,-1

@Wait 0.5
@PlaySoundFile h1040107.wav
If the data is continuous,  for the class 20-29:
'@at ,+1
                    upper bound, or boundary  #^= 29.4
'@at ,-2
                    lower bound, or boundary  #t= 19.5
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@prompt
@keyPoint 9999,comparing frequencies 1

@PlaySoundFile h1040108.wav

#bcomparing frequencies 1#
Frequency is the area of the column for each
'@at ,-2
class. If the columns in the histogram are the
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same width you can compare frequency by
'@at ,-2
comparing the height of each column. The
'@at ,-2
tallest column shows the #hmodal class#.
@atgraphic 50,114
@picture datahand\h0401e.bmp


@prompt
@keyPoint 9999,comparing frequencies 2

@PlaySoundFile h1040109.wav


#bcomparing frequencies 2#
On some histograms, the columns have different
'@at ,-2
widths. To compare the frequencies on these
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histograms, you must compare the areas of the
'@at ,-2
columns. The column with the largest area
'@at ,-2
shows the #hmodal class#.
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@prompt
@keyPoint 9999,summary (part 1)
#bSummary#
@at ,+8
   *   #^The class is always shown on the
#Thorizontal axis (x-axis) of a histogram
@at ,+8
@wait .75
   *   #TFrequency density is always shown on the
#Tvertical axis (y-axis)
@at ,+8
@wait .75
   *   #TThe mid-point of class intervals should be at
#Tthe centre of each rectangle
@at ,+8
@wait .75
   *   #TThe extremes of each column represent the
#Tupper or lower boundaries of each class
@at 175,+5
#b(continued)#



@prompt
@keyPoint 9999,summary (part 2)
#b(continued)#

@wait 0.75

@at ,+8
   *   #^If the columns in the histogram are the
#Tsame, the heights of the columns are used
#Tto compare frequency, with the tallest
#Tcolumn showing the #hmodal class#
@at ,+8
@wait 0.75
   *   #TIf the columns in the histogram are of
#Tdifferent widths, the areas of the columns
#Tare used to compare frequency, and the
#Tcolumn with the largest area shows the
#T#hmodal class#.