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Unformatted text preview: he distribution, the modal class
is determined by the method of grouping.
Steps for Calculation :
We prepare a grouping table with 6 columns
1. In column I, we write down the given frequencies.
2. Column II is obtained by combining the frequencies two
by two.
3. Leave the 1st frequency and combine the remaining
frequencies two by two and write in column III
4. Column IV is obtained by combining the frequencies
three by three.
5. Leave the 1st frequency and combine the remaining
frequencies three by three and write in column V
6. Leave the 1st and 2nd frequencies and combine the
remaining frequencies three by three and write in
column VI
Mark the highest frequency in each column. Then form an
analysis table to find the modal class. After finding the modal class
use the formula to calculate the modal value.
Example 32:
Calculate mode for the following frequency distribution.
Class
interval
Frequency 05
9 Grouping Table
CI
0 5
510
1015
1520
2025
2530
3035
3540 510
12 f
9
12
15
16
17
15
10
13 1015
15 1520
16 2 2025
17 3 21
27 2530
15 4 32
25
23
131 5 3540
13 6 36
43 31
33 3035
10 48
48
42 38 Analysis Table
Columns
1
2
3
4
5
6
Total 05 510 1015 1520 1
1
2 1
1
1
1
4 1
1 2025
1
1
1
1
1
5 2530 3035 3540 1
1 2 The maximum occurred corresponding to 2025, and hence
it is the modal class.
1+ Here l = 20; ×C 1 Mode = Mo = l +
1 2 = f1 − f0 = 17 −16 = 1 2= f1−f2 = 17 − 15 = 2 1
×5
1+ 2
= 20 + 1.67 = 21.67
Graphic Location of mode:
Steps:
1. Draw a histogram of the given distribution.
2. Join the rectangle corner of the highest rectangle (modal
class rectangle) by a straight line to the top right corner of
the preceding rectangle. Similarly the top left corner of the
highest rectangle is joined to the top left corner of the
rectangle on the right.
3. From the point of intersection of these two diagonal lines,
draw a perpendicular to the x axis.
4. Read the value in xaxis gives the mode.
Example 33:
Locate the modal value graphically for the following
frequency distribution.
Class
010...
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This note was uploaded on 01/18/2014 for the course BUS 100 taught by Professor Moshiri during the Winter '08 term at UC Riverside.
 Winter '08
 Moshiri
 Business

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