PPT-Sampling GrowingKnowing.com © 2011

1 Sampling A sample is a subset of the population In a sample you study a few members of the population In a census you study every member of the population If done properly a sample can be accurate and avoid the cost and time needed for a full census . Sampling is perhaps the most important step in assuring that good quality aggregates are being used on INDOT contracts. Since a sample is just a small portion of the total material, the importance th Nepal. FAO-AFMA . Regional Workshop on Sampling for Agricultural Censuses and Surveys Bangkok, Thailand . 14-18 May . 2012. Ambika. . Bashyal. Central Bureau of Statistics. Hem Raj . Regmi. Ministry of Agriculture and Cooperatives. Excel. GrowingKnowing.com © 2011. 1. GrowingKnowing.com © 2011. Estimates. We are often asked to predict the future!. When will you complete your team project?. When will you make your first million dollars?. Excel. GrowingKnowing.com © 2011. 1. GrowingKnowing.com © 2011. There are 5 steps. Step 1: State the null and alternative hypothesis. Step 2: Select a confidence level. Step 3: Determine the decision rule. Excel. GrowingKnowing.com © 2011. 1. GrowingKnowing.com © 2011. Sample size. How big should a sample be for a valid study?. Why phone 10,000 students if phoning 50 is enough?. Large samples take longer and cost more. Manual. GrowingKnowing.com © 2011. 1. GrowingKnowing.com © 2011. Sample size. How big should a sample be for a valid study?. Why phone 10,000 students if phoning 50 is enough?. Large samples take longer and cost more. GrowingKnowing.com © 2011. 1. GrowingKnowing.com © 2011. Binomial probabilities. Your choice is between success and failure. You toss a coin and want it to come up tails. Tails is success, heads is failure. 1. GrowingKnowing.com © 2011. Percentile. What ‘s the difference between percentile and percent?. Percent measures ratio. 90% . percent . on a test shows you got 9 out 10 questions right. . Percentile measures position. 1. GrowingKnowing.com © 2011. Small Samples. If your sample size is below 30, this is a small sample so use the t table, not z.. Decision rule uses =. t.inv. instead of =. normsinv. Excel 2010: . GrowingKnowing.com © 2011. 1. GrowingKnowing.com © 2011. Estimates. We are often asked to predict the future!. When will you complete your team project?. When will you make your first million dollars?. A link between Continuous-time/Discrete-time Systems. x. (. t. ). y. (. t. ). h. (. t. ). x. [. n. ]. y. [. n. ]. h. [. n. ]. Sampling. x. [. n. ]=. x. (. nT. ), . T. : sampling period. x. [. n. ]. x. 1. GrowingKnowing.com © 2011. Binomial probabilities. Your choice is between success and failure. You toss a coin and want it to come up tails. Tails is success, heads is failure. Although you have only 2 conditions: success or failure, it does not mean you are restricted to 2 events. 1. GrowingKnowing.com © 2011. Sample size. How big should a sample be for a valid study?. Why phone 10,000 students if phoning 50 is enough?. Large samples take longer and cost more. What if a sample of 50 is not enough, you need 51 for a valid study?. 7. Introduction. In . a typical statistical inference problem, you want to discover one or more characteristics of a given population. .. However, it is generally difficult or even impossible to contact each member of the population..