Agriculture Reference
In-Depth Information
Table 8.7
Frequency distribution table of yield (q/ha) in 130 paddy varieties
Mid
value (
Cumulative
frequency (CF
Cumulative
frequency (CF
Relative
frequency
Frequency
density
Yield classes
Frequency (
f
i
)
x
i
)
<
)
)
10-20
16
15
16
130
0.123077
5.33
20-30
54
25
70
114
0.415385
18.00
30-40
14
35
84
60
0.107692
4.67
40-50
11
45
95
46
0.084615
3.67
50-60
10
55
105
35
0.076923
3.33
60-70
10
65
115
25
0.076923
3.33
70-80
8
75
123
15
0.061538
2.67
80-90
7
85
130
7
0.053846
2.33
Table 8.8
Frequency distribution table of effective tillers per hill (ETL) in 100 paddy varieties
ETL discrete
classes
ETL continuous
classes
Frequency
(
Mid
value (
Cumulative
frequency (CF
Cumulative
frequency (CF
Relative
frequency
Frequency
density
f
i
)
x
i
)
<
)
)
4-6
3.5-6.5
10
5
10
100
0.10
3.33
7-9
6.5-9.5
22
8
32
90
0.22
7.33
10-12
9.5-12.5
18
11
50
68
0.18
6.00
13-15
12.5-15.5
13
14
63
50
0.13
4.33
16-18
15.5-18.5
17
17
80
37
0.17
5.67
19-21
18.5-21.5
10
20
90
20
0.10
3.33
22-24
21.5-24.5
7
23
97
10
0.07
2.33
25-27
24.5-27.5
3
26
100
3
0.03
1.00
Mid Value
: Mid value of a class is the average of
the lower limit/boundary and the upper limit/
boundary. Mid values are generally taken as
representatives of different classes. In Table
8.1
,
the mid values for different classes are 15, 25,
35,
Cumulative Frequency
: Cumulative frequency of
a class is defined as the number of observations up
to a particular class (
less than type
)orabovea
particular class (
). In our previ-
ous example, if we take the class 12.5-15.5, then
the cumulative frequency (lesser than type) for the
class is 63. This means that there are 63 varieties
of rice which have less than 15.5 number of ETL
per hill. Similarly, the cumulative frequency
(greater than type) for the same class is 50. That
means the number of varieties having 12.5 or
more than 12.5 number of ETL per hill is 39.
Cumulative frequency gives an instant idea
about the distribution of frequencies among the
classes and the cutoff points (Tables
8.7
and
8.8
).
greater than type
...
, etc.
Frequency Density
: As we know it, “density” is
mass per unit volume, that is,
d ¼ m
/
v
gm/cc
where m in gram is the mass for a “
” (cc) of a
matter. Similarly, frequency density is the fre-
quency of a particular class per unit of class
width. In Table
8.2
, the frequency density of the
class 3.5-6.5 is 10/3
v
¼
3.333. Similarly, for
class 6.5-9.5 is 22/3
7.33. Frequency density
indicates the concentration of observations in
different classes of a frequency distribution
table per unit of class width.
¼
8.1.4 Presentation of Information
Relative Frequency
: Relative frequency is
defined as the proportion of observation in a par-
ticular class to a total number of observations.
Thus, in Table
8.2
, the relative frequency of the
class 3.5-6.5 is 10/100
Edited/scrutinized data can either be used for the
application of statistical methodologies and/or
presented in a suitable form to present and con-
cise the information from the recorded data. In
the following sections, discussion has been made
0.10. Sometimes, the
relative frequency is expressed in percentage also.
¼
