4.4 I FUNDAMENTALS OF BUSINESS MATHEMATICS AND STATISTICSStatistical Representation of Data
Classification according to Attributes :
(i) Simple classification is that when one attribute is present i.e. classification of persons according to sex
–males or female.
(ii) Manifold classification is that when more than one attributes are present simultaneously two attributes
–deafness and sex. A person may be either deaf or not deaf, further a person may be a male or a
female. The data, thus are to be divided into four classes :-
(a) males who are deaf,
(b) males who are not deaf,
(c) females who are deaf,
(d) females who are not deaf.
The study can be further continued, if we find another attribute, say religion.
Classification according to Class-intervals :
The type arises when direct measurements of data is possible. Data relating to height, weight, production
etc. comes under this category. For instance persons having weight, say 100-110 Lbs, can form one group,
110-120 lbs. another group and so on. In this way data are divided into different classes ; each of which is
known as class interval. Number of items which fall in any class-interval is known as class frequency. In the
class-intervals mentioned above, the first figures in each of them are the lower limits, while the second
figure are the upper limits. The difference between the limits of a class interval is known as magnitude of
the class interval. If for each class intervals the frequencies given are aggregates of the preceding
frequencies, they are known as cumulative frequencies. The frequencies may be cumulated either from
top or from below.
DISCRETE AND CONTINUOUS SERIES :
Statistical series may be either discrete or continuous. A discrete series is formed from items which are
exactly measurable, Every unit of data is separate, complete and not capable of divisions. For instance,
the number of students obtaining marks exactly 10, 14, 18, 29, can easily be counted. But phenomenon like
height or weight cannot be measured exactly or with absolute accuracy. So the number of students (or
individuals) having height exactly 5’ 2” cannot be counted. Exact height may be either 5’2” by a hundredth
part of an inch. In such cases, we are to count the number of students whose heights lie between 5’ 0” to
5’ 2”. Such series are known as ‘continuous’ series.
Example 1:
Discrete Series Continuous Series
Marks No. of Students Height (inch) No. of students
10 12 58 – 60 6
14 16 60 – 62 10
18 15 62 – 64 13
20 7 64 – 66 11
4.1.4.2. TABULATION :
Tabulation is a systematic and scientific presentation of data in a suitable form for analysis and interpretation.
After the data have been collected, they are tabulated i.e. put in a tabular form of columns and rows. The
function of tabulation is to arrange the classified data in an orderly manner suitable for analysis and
interpretation. Tabulation is the last stage in collection and compilation of data, and is a kind of stepping-
stone to the analysis and interpretation.