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For example, let the design effect, for estimating the population mean based on some sampling design, be 2. If the sample size is 1,000, then the effective sample size will be 500. It means that the variance of the weighted mean based on 1,000 samples will be the same as that of a simple mean based on 500 samples obtained using a simple random ...
A practice effect is the outcome/performance change resulting from repeated testing. This is best described by the Power Law of Practice : If multiple levels or some other variable variation are tested repeatedly (which is the case in between-group experiments), the subjects within each sub-group become more familiarized with testing conditions ...
This example of design experiments is attributed to Harold Hotelling, building on examples from Frank Yates. [21] [22] [14] The experiments designed in this example involve combinatorial designs. [23] Weights of eight objects are measured using a pan balance and set of standard weights. Each weighing measures the weight difference between ...
A Design of Experiments will result in a set of design points, and each design point is designed to be executed one or more times, with the number of iterations based on the required statistical significance for the experiment. Effect (of a factor): How changing the settings of a factor changes the response.
In the first example provided above, the sex of the patient would be a nuisance variable. For example, consider if the drug was a diet pill and the researchers wanted to test the effect of the diet pills on weight loss. The explanatory variable is the diet pill and the response variable is the amount of weight loss.
Design and Analysis of Experiments. Handbook of Statistics. Vol. 13. North-Holland. ISBN 978-0-444-82061-7. "Model Robust Designs". Design and Analysis of Experiments. Handbook of Statistics. pp. 1055– 1099. Cheng, C.-S. "Optimal Design: Exact Theory". Design and Analysis of Experiments. Handbook of Statistics. pp. 977– 1006.
An example of an unrandomized design would be to always run 2 replications for the first level, then 2 for the second level, and finally 2 for the third level. To randomize the runs, one way would be to put 6 slips of paper in a box with 2 having level 1, 2 having level 2, and 2 having level 3.
Many significance tests have an estimation counterpart; [26] in almost every case, the test result (or its p-value) can be simply substituted with the effect size and a precision estimate. For example, instead of using Student's t-test, the analyst can compare two independent groups by calculating the mean difference and its 95% confidence ...