Successful statistical practice is based on focused problem definition. In sampling, this includes defining the "population" from which our sample is drawn. A population can be defined as including all people or items with the … See more

Within any of the types of frames identified above, a variety of sampling methods can be employed individually or in combination. Factors commonly influencing the … See more

Formulas, tables, and power function charts are well known approaches to determine sample size.
Steps for using sample size tables:
1. Postulate the effect size of interest, α, and β.
2. Check sample size table See more

Sampling enables the selection of right data points from within the larger data set to estimate the characteristics of the whole population. For example, there are about 600 million tweets produced every day. It is not necessary to look at all of them to determine the … See more

In the most straightforward case, such as the sampling of a batch of material from production (acceptance sampling by lots), it would be most desirable to identify and measure every … See more

Sampling schemes may be without replacement ('WOR' – no element can be selected more than once in the same sample) or with replacement ('WR' – an element may appear multiple times in the one sample). For example, if we catch fish, measure them, and … See more

Good data collection involves:
• Following the defined sampling process
• Keeping the data in time order See more