Lecture

Understanding Statistics & Experimental Design

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In course

BIO-449: Understanding statistics and experimental design

This course is neither an introduction to the mathematics of statistics nor an introduction to a statistics program such as R. The aim of the course is to understand statistics from its experimental design and to avoid common pitfalls of statistical reason ...

Description

This lecture covers the impact of unequal variances on Type I error rates in hypothesis testing, the importance of replication in scientific studies, the concept of power in hypothesis testing, and the effects of effect size on statistical power. It also discusses biases such as optional stopping, publication bias, and data peeking, and their implications on research outcomes. The instructor presents simulated experiments to demonstrate these concepts and highlights the challenges of interpreting statistical results in the presence of biases.

Instructor

Michael Herzog

Teaching & PhD PhD Students Sandrine Brikh, Melissa Mohamad Allouche, Ece Yatikçi, Melissa Faggella, Elsa Scialom, Marie Isabelle Holdsworth, Martina Morea, Pierre Merret, Sandali Nisansa Liyanagoonawardena Past EPFL PhD Students Frank Scharnowski, Thomas Otto, Toni Saarela, Elisa Tartaglia, Bilge Sayim, Johannes Rüter, Marco Boi, Kristoffer Aberg, Yvonne Evelina Thunell, Mauro Manassi, Vitaly Chicherov, Lukasz Grzeczkowski, Marc Michael Lauffs, Ophélie Favrod, Janir Nuno Ramos da Cruz, Adrien Doerig, Lei

Official source

Ontological neighbourhood

Statistics

Statistical inference: Statistical hypothesis testing

Related concepts (32)

Statistical hypothesis testing

A statistical hypothesis test is a method of statistical inference used to decide whether the data at hand sufficiently support a particular hypothesis. Hypothesis testing allows us to make probabilistic statements about population parameters. While hypothesis testing was popularized early in the 20th century, early forms were used in the 1700s. The first use is credited to John Arbuthnot (1710), followed by Pierre-Simon Laplace (1770s), in analyzing the human sex ratio at birth; see .

Effect size

In statistics, an effect size is a value measuring the strength of the relationship between two variables in a population, or a sample-based estimate of that quantity. It can refer to the value of a statistic calculated from a sample of data, the value of a parameter for a hypothetical population, or to the equation that operationalizes how statistics or parameters lead to the effect size value. Examples of effect sizes include the correlation between two variables, the regression coefficient in a regression, the mean difference, or the risk of a particular event (such as a heart attack) happening.

Selection bias

Selection bias is the bias introduced by the selection of individuals, groups, or data for analysis in such a way that proper randomization is not achieved, thereby failing to ensure that the sample obtained is representative of the population intended to be analyzed. It is sometimes referred to as the selection effect. The phrase "selection bias" most often refers to the distortion of a statistical analysis, resulting from the method of collecting samples. If the selection bias is not taken into account, then some conclusions of the study may be false.

Bias

Bias is a disproportionate weight in favor of or against an idea or thing, usually in a way that is closed-minded, prejudicial, or unfair. Biases can be innate or learned. People may develop biases for or against an individual, a group, or a belief. In science and engineering, a bias is a systematic error. Statistical bias results from an unfair sampling of a population, or from an estimation process that does not give accurate results on average. The word appears to derive from Old Provençal into Old French biais, "sideways, askance, against the grain".

Test statistic

A test statistic is a statistic (a quantity derived from the sample) used in statistical hypothesis testing. A hypothesis test is typically specified in terms of a test statistic, considered as a numerical summary of a data-set that reduces the data to one value that can be used to perform the hypothesis test. In general, a test statistic is selected or defined in such a way as to quantify, within observed data, behaviours that would distinguish the null from the alternative hypothesis, where such an alternative is prescribed, or that would characterize the null hypothesis if there is no explicitly stated alternative hypothesis.

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