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The table shown on the right can be used in a two-sample t-test to estimate the sample sizes of an experimental group and a control group that are of equal size, that is, the total number of individuals in the trial is twice that of the number given, and the desired significance level is 0.05. [4]
In survey sampling, weights can be applied to the data to adjust for the sample design, particularly in stratified sampling. [1] Results from probability theory and statistical theory are employed to guide the practice. In business and medical research, sampling is widely used for gathering information about a population. [2]
A research question is "a question that a research project sets out to answer". [1] Choosing a research question is an essential element of both quantitative and qualitative research . Investigation will require data collection and analysis, and the methodology for this will vary widely.
For qualitative research, the sample size is usually rather small, while quantitative research tends to focus on big groups and collecting a lot of data. After the collection, the data needs to be analyzed and interpreted to arrive at interesting conclusions that pertain directly to the research question.
An N of 1 trial (N=1) is a multiple crossover clinical trial, conducted in a single patient. [1] A trial in which random allocation is used to determine the order in which an experimental and a control intervention are given to a single patient is an N of 1 randomized controlled trial .
In addition, we suppose that the measurements X 1, X 2, X 3 are modeled as normal distribution N(μ,2). Then, T should follow N(μ,2/) and the parameter μ represents the true speed of passing vehicle. In this experiment, the null hypothesis H 0 and the alternative hypothesis H 1 should be H 0: μ=120 against H 1: μ>120.
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The variance of the estimate X 1 of θ 1 is σ 2 if we use the first experiment. But if we use the second experiment, the variance of the estimate given above is σ 2 /8. Thus the second experiment gives us 8 times as much precision for the estimate of a single item, and estimates all items simultaneously, with the same precision.