The Problem Of Planning Essay Example | Topics and Well Written Essays - 1500 words

The Problem Of Planning - Essay Example In statistical terms, random sample means the set of items that are drawn from a large set of items (population) and it is the subset of the population. The method of sample satisfies the criterion of randomness, that is, each item has equal chance to be drawn or selected. The only factor an item to be selected is mere chance. But in order to ensure the equal chance to all items, once an item is selected, it should be replaced by the population. If the population consists of heterogeneous subgroups or different strata, it would be advisable to sample each subpopulation (stratum) separately. Stratification is the process of grouping members into relatively homogenous groups. The random sampling is applied within each stratum. This method of random sampling from different strata improves the representative nature of the sample by reducing the sampling error. The sample size is the number of observations that constitute the sample and it is normally represented by an integer (positive number). The sample size is determined by a number of factors like convenience, time, money and the purpose of the study. But in many cases, the decision of sample size becomes confusing. Though the published literature on this issue is not very much rich in comparison to its importance, there are articles and books which are concerning the sample size determination. Some of them are Kraemer and Thiemann (1987), Cohen (1988), Lipsey (1990), Shuster (1990), and Odeh and Fox (1991). Determining Sample Size is such an important issue that the reliability of the results mainly depends on this. The decision of how large would be a sample is so important that it enables the statistical judgments would be accurate and reliable. For this, the sample size should not be too small or too large.