Recent content by sfs01

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    News Greece, Italy and the Euro

    The glaring omission in that article is however the same statistic for the UK, with aggregate debt at 469%. Even after gratuitously subtracting the contribution of the London financial sector, it remains above that of Spain in the underlying source...
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    News Why I am not always convinced living in EU makes sense

    Would like to point out that this has little to do with the EU as such, but is the UK's overzealous interpretation of EU law. The UK, especially with health and safety regulations, are masters at coming up with bizarre rules and then blaming the bizarreness on EU rules although strangely no...
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    Schools King's College London (KCL) undergrad physics?

    Think the Physics dept at KCL is fairly small, which might explain the variability in rankings. That doesn't mean it's bad, but might mean less choice, if you're looking to to get involved in undergrad research depending on which areas you find interesting.
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    Dutch words for hydrogen and oxygen

    The words Oxygen and Hydrogen have the same meaning - i.e. acid creator and water creator in Latin, respectively. Only difference is that their names were translated into Dutch and German, whereas English retained the Latin name. The discovery that the chemistry actually works differently was...
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    Chi-squared inverse function and incomplete gamma function

    If you just want the quantile (inverse CDF) of the chi squared distribution, that can be approximated with the normal distribution inverse CDF for large numbers of degrees of freedom. That isn't known analytically either, but matlab etc. have good approximations. Or do you want something...
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    GPA: Can you be too perfect?

    That's how college exams work in many countries anyhow. E.g. In the UK an A corresponds to a mark of 70% and someone ever getting close to 100% is exceedingly rare in an individual exam, let alone consistently, would say the average is usually around 60%. Everything's still based on the...
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    Chi or Rayleigh or Ricean?

    And don't think you'll get a nice analytic distribution for this. There seem to be a few numerical methods out there for managing the distribution of a linear combination of non-central chi squared random variables though, which is fairly close to what you want (apart from the square root)
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    Chi or Rayleigh or Ricean?

    Err, sorry, got a bit over-enthusiastic and thought it should fit nicely, but seems it doesn't after all, so yes looks more complicated.
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    Chi or Rayleigh or Ricean?

    It's a non-central chi distribution.
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    Can someone explain this step in the proof of the convolution theorem?

    After the substitution, y is just a dummy variable and consequently independent of x. If it was a definite integral, the substitution would have moved the dependency on x to the integral limits but because the integral is over all space, they are still independent of x after the substitution.
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    Disjoint / Independent?

    Which events are meant to be both independent and disjoint in this case? The only way I can see that two events can ever be both independent and disjoint is if one of them has probability zero. The main events for the coin tosses are - the two events representing the results of each...
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    Disjoint / Independent?

    No, that only works for disjoint events, generally P(A\cup B) = P(A) + P(B) - P(A\cap B) so for disjoint events the third term is zero.
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    Disjoint / Independent?

    Disjoint events are mutually exclusive, which is a strong form of statistical dependence (so if you know event A occurred you know that B definitely did not occur and vice versa), meaning P(A\cap B) = 0 For events to be independent on the other hand, knowing if one event occurred does not...
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    Relation between exponentially distributed random variables and Poisson(1)

    For fixed n, the condition X_k = log ( n ) gives you a probability for each of the exponential random variables to be included in the count. So, what distribution does that mean N has in terms of n, k and that probability? The limit of that distribution as n goes to infinity should then be...
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    How irrational are employers on the topic of related disciplines?

    And yes, for software development roles, people do filter by degree specialisation, but usually the criterion is something like 'a degree in a numerate/technical subject' rather than just CS. So you should be fine with a math degree, if you can show some motivation about why you want to do...