# tutorial_8 - (Hint National Park survey example 2...

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2012/13 Semester 2 Tutorial 8 ST3239 1. In an aerial survey of four plots selected by simple random sampling, the numbers of ducks detected were 44, 55, 4, and 16. Careful examination of photoimagery of the first and third of these plots (selected as a simple random subsample) revealed the actual presence of 56 and 6 ducks, respectively. The study area consists of 10 plots. (a) Estimate the total number of ducks in the study area by using a ratio estimator. Estimate the variance of the estimator. (b) Can you suggest another estimator different from the one in (a)? Get an estimate of the total number of ducks and also an estimate of its variance.
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Unformatted text preview: (Hint: National Park survey example.) 2. Systematic sampling is used in exit poll during election in the US. The reason is because the size of the votes at a voting centre is not known in advance. So, when your friend asks you to help her to design a survey to estimate the profile of people visiting her website on a particular day, you right away think of this particular sampling scheme because the size of visitors to the her website on that chosen day is also unknown. (a) Do you think the characteristics of the two studies are the same? (b) If not, how do you modify your study in order to meet your friend’s request?...
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