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Articles related to "analysis"


One-tailed or two-tailed test, that is the question

  • An important characteristic of the one-tailed test is that it provides more power to detect an effect in one direction, as it does not test the other one.
  • We should never select the one-tailed test for the sole purpose of obtaining statistical significance, as this can lead to an invalid conclusion and in some cases dire consequences.
  • With a 5% significance level, the sample mean is considered significantly different from x when the test statistic falls into the critical region — the bottom AND top 2.5% of the test statistic’s probability distribution.
  • This results in a p-value of less than 0.05 and indicates we should reject the null hypothesis in favor of the alternative one.
  • With the obtained p-value < 0.05we have reasons to reject the null hypothesis in favor of the alternative.

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Reduce Dimensions for Single Cell

  • Here we see that most of the non-linear dimensionality reduction techniques have successfully resolved the small yellow cluster via preserving the local structure (connections between neighboring points) of the data.
  • In contrast, UMAP preserves both the local and the global data structure and is based on the topological data analysis where a manifold is represented as a collection of elementary Simplex units, this ensures that the distances between the data points do not look all equal in the high-dimensional manifold but there is a distribution of distances similar to the 2D space.
  • In this post, we have learnt that single cell genomics data have a non-linear structure which comes from the large proportion of stochastic zeros in the expression matrix due to the drop out effect.
  • In contrast, preserving the local connectivity between the data points (LLE, tSNE, UMAP) is the key factor for a successful dimensionality reduction of single cell genomics data.

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One-tailed or two-tailed test, that is the question

  • An important characteristic of the one-tailed test is that it provides more power to detect an effect in one direction, as it does not test the other one.
  • We should never select the one-tailed test for the sole purpose of obtaining statistical significance, as this can lead to an invalid conclusion and in some cases dire consequences.
  • With a 5% significance level, the sample mean is considered significantly different from x when the test statistic falls into the critical region — the bottom AND top 2.5% of the test statistic’s probability distribution.
  • This results in a p-value of less than 0.05 and indicates we should reject the null hypothesis in favor of the alternative one.
  • With the obtained p-value < 0.05we have reasons to reject the null hypothesis in favor of the alternative.

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Earth's inner core is doing something weird

  • Now, the records of these wiggles are making waves among geologists: They have helped scientists calculate one of the most precise estimates yet of how fast the planet’s inner core is spinning.
  • Previous work, including the paper Richards coauthored, used various properties of earthquake waves traveling through the planet to deliver their estimates for the inner core’s super-rotation, with several sitting around a few tenths of a degree a year.
  • Earle, Vidale, and Doug Dodge of Lawrence Livermore National Laboratory used the scattered waves from these nuclear explosions to peer into the planet’s core.
  • By comparing the fingerprint of waves scattered back from explosions at nearly the same location in 1971 and 1974, the team could calculate how much faster the inner core turned relative to the rest of the planet.

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These are the top five trends shaping the future of digital health

  • The healthcare industry is in a state of disruption.
  • Digital solutions are becoming a necessary part of the new global standard of care for patients and regulation is being fast-tracked to catch up to digital health innovation.
  • These rapid changes will have ripple effects across the entire healthcare system, impacting incumbents and new entrants alike.
  • Based on our ongoing analysis, understanding of industry trends, and conversations with industry executives, Business Insider Intelligence, Business Insider’s premium research service, has put together The Top Five Trends Shaping The Future of Digital Health.
  • This exclusive report can be yours for FREE today.
  • Copyright © 2018 Insider Inc. All Rights Reserved.

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r/algotrading - I've reproduced 130+ research papers about "predicting the stock market", coded them from scratch and recorded the results. Here's what I've learnt.

  • For example, one paper adds engineered features to the price then says "then we ran the data through our model" - it's not clear if it means the original data or the engineered data, so I tried both ways.
  • Probably the most complex AND vague in terms of methodology and after weeks trying to reproduce their results (and failing) I figured out that they were leaking future data into their training set (this also happens more than you'd think).
  • Also one other thing I'd like to add, even the Godfather of value investing, the late Benjamin Graham (Warren Buffet's mentor) used to test his strategies (even though he'd be trading manually) so literally every investor needs to backtest regardless of if you're day-trading or long-term investing or building trading algorithms.

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ProBeat: Breakthrough or BS, Amazon’s Rekognition is dangerous

  • But no issue has been as contentious this year as selling its facial recognition tech Rekognition to law enforcement.
  • AWS comes under fire for Rekognition sales to the federal government, who in turn is building concentration camps for children, and AWS's response is to improve "age range estimation" and "fear detection" in the service?
  • Amazon Rekognition provides a comprehensive set of face detection, analysis, and recognition features for image and video analysis.
  • Improved face analysis models are now available for both Amazon Rekognition Image and Video, and are the new default for customers in all supported AWS regions.
  • Amazon’s Rekognition cannot detect human emotion because doing so is not technically possible using facial recognition.
  • The former means that Amazon is selling a product that claims to detect emotion when all it’s really detecting is facial movements that may or may not be related.

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