Teens-and-Mobile-Phones (1)

# 1 767 contact rate pew internet american life project

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Unformatted text preview: .6 16.6 15 16.7 17.8 16.8 16.7 16.3 16.7 Kid ’s Sex Kid ’s Age Pew Internet & American Life Project 16 Teens and Mobile Phones | 162 15 16.7 17.8 16.8 16 16.7 16.3 16.7 17 16.7 19.1 17.0 Effects of Sample Design on Statistical Inference Post -data collection statistical adjustments require analysis procedures that reflect departures from simple random sampling. PSRAI calculates the effects of these design features so that an appropriate adjustment can be incorporated into tests of statistical significance when using these data. The so -called "design effect" or deff represents the loss in statistical efficiency that results from systematic non -response. The total sample design effect for this survey is 1.18. PSRAI calculates the composite design effect for a sample of size n, with each case having a weight, wi as: In a wide range of situations, the adjusted standard error of a statistic should be calculated by multiplying the usual formula by the square root of the design effect (√ deff ). Thus, the formula for computing the 95% confidence interval around a percentage is:...
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