(a) Primary Data: Primary data is the data collected for the first time by an investigator or agency who makes use of the data for the first time. It is in the shape of raw material and after a use, is converted into a secondary data. This data is collected originally and needs more precaution at the time of collection but less at the time of its use. For example, raw materials
used in products.
(b) Secondary Data: This data is collected for the second time or any subsequent time by an investigator who makes use of the data for any subsequent time. It is already available and is not original. It needs at the time of collection less precaution but more at the time of use. For example, finished goods capable of further processing.
Q.11. What is analysis of variance? Explain its testing procedure when data is classified according to two-way.(2006-07)
Ans. Analysis of Variance: Analysis of variance (abbreviated as ANOVA) is useful in the fields of economics, biology, education, psychology, sociology, business, industry and in researches of several other disciplines. This technique is used when multiple sample cases are involved. For example, the significance of the difference between the means of two samples can be judged through either Z-test or the t-test, but the difficulty arises when we happen to examine the significance of the difference amongst more than two sample means at the same time. The ANOVA technique enables us to perform this simultaneous test and as such is considered to be an important tool of analysis in the hands of a researcher. Using this technique, one can draw inferences about whether the samples drawn from populations have the same mean.
Variance Analysis in Two Way Classification: In two-way classification, the effect of one factoris studied through the columnwise figures and totals and the other through the rowwise figures and totals. The variances are calculated for both the columns and rows and they are compared with the residual variance.
Table of Variance in Two-way Classification