Collections and Prestation of Data

• In conducting a research or a study, the first major step is the collection of statistical data.
• Sampling Techniques:

  • lower cost
  • faster data collection
  • homogeneity and quality of the data
• Simple Random Sampling - each element of the frame has an equal chance of being chosen. The values are selected independently from the population.
• Stratified Random Sampling - if the population embraces a number of distinct categories, this is used to avoid bias in the selection of samples. The population will be divided into categories strata and from these categories, the membes members will be drawn proportionally
• Systematic Sampling - starts with arranging the population to some ordering scheme, and then selecting elements at regular intervals through the ordered list.
• Cluster Sampling - used if the population is spread out over a wide area. It is more cost-effective to select the elements in group or clusters.