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2h
comment Why is a moment called a moment?
The concept is more like moment of inertia
1d
comment What is zero mean and unit variance in terms of image data?
Actually variance is the average of the squares of differences from the mean. Are you asking about "standardisation" or "rescaling"as preprocessing step? It is designed to avoid a single explanatory variable dominating the others just because it has a wide range of numerical values.
Apr
27
answered Naive Bayes: Intuition behind the Evidence
Apr
26
comment 'Level' still seems periodic after Season Decomposition
A couple of points to consider: (1) the range of "level" is about $0.05$ (and the daily fluctuation even smaller) compared with $0.25$ for "season1" and (2) you you might take averages of level for individual hours (ignoring days) to see if there is a much of a pattern. My guess is that the real daily seasonal pattern changed very slightly from beginning to end (especially in the final $8$ days) and this is causing some of the apparent pattern in "level"
Apr
26
revised Can this be analyzed with a parametric analysis?
layout
Apr
26
comment Filter only names of Cities from datasets
Not a Cross Validated question. How would you know that Alert might be a geographical name?
Apr
26
comment Estimator of true probability — understanding margin of error for very small probability
It looks like it. Note that $\tilde{p}$ is slightly different to $\hat{p}$
Apr
26
comment Estimator of true probability — understanding margin of error for very small probability
The issue is the line $\displaystyle s_p = \sqrt{ \frac {p \, (1-p) } {n} } \le \sqrt{ \frac {0.5 \times 0.5 } {n} } = \frac {1}{2 \, \sqrt{n}}$ related to the title of the article Checking whether a coin is fair. If instead $p$ is close to $0$ or $1$, then $s_p$ will be much smaller. You might want to read the Wikipedia article Binomial proportion confidence interval which has some other approaches
Apr
25
comment What transformation should I use for a bimodal distribution?
@M.Beausoleil - in that case you really do not want to remove the bimodality, as it will reduce the discrimination of your analysis
Apr
25
answered What transformation should I use for a bimodal distribution?
Apr
25
awarded  Enlightened
Apr
25
awarded  Nice Answer
Apr
24
comment Distribution of sum of squared normals, scalar form
Consider en.wikipedia.org/wiki/Noncentral_chi-squared_distribution
Apr
21
answered Percentage points for W in Worsley (1979, JASA)
Apr
20
comment Making sense of Binominal GLM model
Perhaps this is telling you that a polynomial fit is not a good idea
Apr
20
comment Adding Normal Distributions
Your "standard formula" for $Z$ assumes independence between scores on the two tests. Is that true in your example?
Apr
20
comment Convergence in distribution of the following sequence of random variables
If it converges, then it converges to a distribution with point probabilities at $0$ and $1$, and which has an expectation of $\frac{\alpha}{ \alpha + \beta}$, so that gives you something to aim for
Apr
12
comment For a standard normal distribution, are p-values calculated using a $\Phi(-Z)$ or $\Phi(Z)$?
$\left|\dfrac{X-\mu}{\sigma}\right|$ will be non-negative, with the consequence that $2\Phi\left(\left|\dfrac{X-\mu}{\sigma}\right| \right) \ge 1$ so is unlikely to give a probability
Apr
11
comment unbiased estimate for household size
Note that if a village had half its households size $2$ and half size $6$ (so three-quarters of the inhabitants of the village lived in households size $6$), and you asked everybody in the village (e.g. stopping them in the street) then the average response would be $5$, while if you knocked at each door and asked the person opening the door, the average response would be $4$
Apr
5
answered Strong Vs Weak law of large numbers, (looking for Stat help and R simulation.)