For 30-50 years of data, a 2 parameter distribution is recommended, and for more than 50 years of data, a 3 parameter distribution should be used. If less than 30 years of local data is available, an index flood approach is recommended where the local observations are used for estimating the index flood and regional data are used for estimating the growth curve. In Norway, the current guidelines for design flood estimates give recommendations on which data, probability distribution, and method to use dependent on length of the local record. Flood inundation maps used for land use planning are also produced based on design flood estimates. Kobierska, Florian Engeland, Kolbjorn Estimation of design floods forms the basis for hazard management related to flood risk and is a legal obligation when building infrastructure such as dams, bridges and roads close to water bodies.The two-stage design can be a useful tool to determine the sample size of high-dimensional studies if in the planning phase there is high uncertainty regarding the expected effect sizes and variability. The false discovery rate (FDR) is controlled despite of the data dependent choice of sample size. The proposed procedure controls the power in all considered scenarios except for very low first stage sample sizes.

The second stage sample size is chosen based on these estimates to achieve a specific overall power. We propose a two-stage design with an adaptive interim analysis where these quantities are estimated from the interim data.

Zehetmayer, Sonja Graf, Alexandra C Posch, Martin Sample size calculations for gene expression microarray and NGS-RNA-Seq experiments are challenging because the overall power depends on unknown quantities as the proportion of true null hypotheses and the distribution of the effect sizes under the alternative.

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