Q.9. Write a note on association of attributes.
Or Write a note on techniques of association of attributes.
Give the Methods of determining attributes.
Ans. Association of Attributes: The prescence of an attribute is usually denoted by capital letters A,B,C and so on, whereas the absence of an attribute is denoted by greek letters a,b, y where a means not a and same as others. A, b, y are called complementary attributes of a, b and c. the combination of different attributes is denoted by AB, Ac., aß, etc.
Methods of Determining Attributes: In order to ascert not, the following methods may be used:
1. Comparison of Observed and Expected Frequencies Method: when this method is applied the actual observation is com expectation, the attributes are said to be independent; 11 expectation, the attributes are said to be positively associated and if the actual the expectation, the attributes are said to be negatively associated.
2. Proportion Method: Under this method, the ratios or the prop are compared. If there exists no relationship between two attributes A and proportion of A’s amongst thea’s and B’s as amongst the B’s and the proportion of Bsam whecame as that amongst the di’s. For example, if a coin is tossed we expect irrespective of whether the coin is tossed by the right hand or the left hand.
3. Yule’s Coefficient of Association: Prof. Yule has suggested the following formula to measure the association:
5 Coefficient of Contingency (Karl Pearson’s): Classification of data can be either dichotomous or manifold. When the universe is divided into two groups, say, ‘rich’ and ‘not rich’–‘A’ and ‘not A’. but a universe may also be divided into a number of parts by a similar process. Thus, attribute ‘A’ may be sub divided in A 4 A. etc. Similarly, another attribute, say B can be sub-divided into B, B9, B,, etc. The frequency falling within the different classes can be arranged in the form of a contingency table.
Q.10. What is data? Give two examples of primary and secondary data.(2014-15)
Ans. Data. Data is a single piece of information. It may consist of numbers, words or images or even a set of variables. It is viewed as a lowest level of abstraction from information and knowledge can be easily retrieved and derived from it.
1. Internal Data: The data generated by different organisations and government department their routine works is called internal data. For example, number of patients in the O.P.D. of a hos number of students admitted in a particular course in a university every year, number of birth number of deaths, number of infant deaths occurred every day in a certain area, etc. This type of data always available from the records of the concerned department and therefore can be picked up from any statistical investigation.
2. External Data: The data collected by some external agency for a certain purpose is called external data. It may be collected by either census method or sample survey ervey method. In census method. gata intormation is collected from each and every unit of the population – survey, information is collected on some part (fraction) of the populace conulation concerned. For example, in India census is conducted after every ten years, while in socio-economic survey, data is collected different social and economic aspects like price, sales, production, etc. from primary source or secondary source. Thus, the external data can be further classified as.
(a) Primary data and (b) Secondary data.