The definition tag has no wiki summary.
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0answers
28 views
Some clear range and interval definitions
What is your or an offical (please provide link to citation) definition of range AND interval _?
Or perhaps put in another way: what is the major important difference between the two terms _?
In my ...
2
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2answers
52 views
Forecasting the past?
More of a literacy question that stats, but I'm looking for correct terminology and the Google machine hasn't thrown anything up.
You have explanatory data and observed data for 2000-2010. You have ...
1
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0answers
41 views
What is meant by the “level” of a time series?
In much of the literature I'm studying it's one of those terms that occurs frequently yet without a rigorous definition to be found. Specifically, I am told:
For time-indexed random variables ...
0
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1answer
73 views
Searching for a Statistical Word
There's a word for when one category under a given condition 'steals' from another. For example, from class now, when french music is played in wine sections of grocery stores people buy more french ...
0
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1answer
76 views
Can a confounding variable be correlated with the DV and not the IV?
Can a confounding variable be correlated with the DV and not the IV?
I have heard of the DV being corr. but I can't find IV in any textbooks.
I found this def. in Wiki:
...
3
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2answers
711 views
Difference between superpopulation and infinite population
What is the difference between Superpopulation and Infinite population? Please explain this with examples.
Thanks!
2
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2answers
204 views
Arbitrariness of Euler's number in exponential of log-normal distribution
The Wikipedia article of the log-normal distribution says
If $X$ is a random variable with a normal distribution, then $Y = \exp(X)$
has a log-normal distribution; likewise, if $Y$ is
...
1
vote
2answers
119 views
What's the difference between likelihood and confidence in claim being true
I'm reading the IPCC report on climate change from 2007.
In their uncertainity guide they make a distinction between likelihood and levels of confidence.
What's the difference between the terms?
...
8
votes
2answers
1k views
Do you reject the null hypothesis when $p < \alpha$ or $p \leq \alpha$?
This is clearly just a matter of definition or convention, and of almost no practical importance. If $\alpha$ is set to its traditional value of 0.05, is a $p$ value of 0.0500000000000... considered ...
1
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2answers
150 views
How is the standard definition of independence applied to time-series?
So, [Wikipedia says] that the standard definition of independence is:
$f_{X,Y}(x,y) = f_X(x) f_Y(y)$
How is this applied to timeseries? How do we calculate each side of the equation?
If we're ...
1
vote
0answers
73 views
How do you call a situation or a point at wich statistics data stops changing?
When I calculate a prediction, for instance I am trying to find out who is going to win elections and I do that by asking people who they voted on. After a certain number of answers my data will stop ...
1
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0answers
126 views
Length weighted median
In the field of genome assemblies in biology (the problem being reconstructing the genome from many, short random pieces of it, where a genome is one or more long strings of a limited alphabet), there ...
4
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1answer
4k views
What is the difference between “margin of error” and “standard error”?
Is "margin of error" the same as "standard error"?
A (simple) example to illustrate the difference would be great!
3
votes
1answer
481 views
Are nominal attributes strict classifications and equivalent to enumerations in programming languages?
I've been looking random forest algorithms for text classification and referencing the Mahout random forest decision tree description. In it, there is a reference to two types of variables, nominal ...
2
votes
3answers
623 views
Degrees of freedom for Chi-squared test
I am facing the following dilemma. I am aware of how to handle the one-sided Chi-distribution, but I am falling victim to how to handle degrees of freedom. Let me clarify with an example what I mean.
...
6
votes
4answers
381 views
Difference between the terms 'joint distribution' and 'multivariate distribution'?
I am writing about using a 'joint probability distribution' for an audience that would be more likely to understand 'multivariate distribution' so I am considering using the later. However, I do not ...
31
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7answers
2k views
Rigorous definition of an outlier?
People often talk about dealing with outliers in statistics. The thing that bothers me about this is that, as far as I can tell, the definition of an outlier is completely subjective. For example, ...
32
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7answers
2k views
What, precisely, is a confidence interval?
I know roughly and informally what a confidence interval is. However, I can't seem to wrap my head around one rather important detail: According to Wikipedia:
A confidence interval does not ...
30
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5answers
14k views
What is the difference between fixed effect, random effect and mixed effect models?
In simple terms, how would you explain (perhaps with simple examples) the difference between fixed effect, random effect and mixed effect models?
2
votes
3answers
915 views
Calculation of incidence rate for epidemiological study — prevalence rate this time
Thanks for all the answer for the question Calculation of incidence rate for epidemiological study in hospital. And here come's the second part of the question:
What about the prevalence rate then? I ...
4
votes
3answers
5k views
Calculation of incidence rate for epidemiological study in hospital
I have kinda puzzled when I heard from the other about the calculation of incidence rate
From Kenneth Rothman's Modern Epidemiology, the incidence rate is calculated as ...
8
votes
4answers
18k views
What is the difference between effectiveness and efficacy in determining the benefit of therapy 'A' on condition 'B'?
The context of this question is within a health framework i.e. looking at one or more therapies in the treatment of a condition.
It appears that even well respected researchers confuse the terms ...
6
votes
1answer
834 views
What is the precise definition of a “Heywood Case”?
I had been using the term "Heywood Case" somewhat informally to refer to situations where an online, 'finite response' iteratively updated estimate of the variance became negative due to numerical ...
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3answers
2k views
What practical implications/interpretations are there of a kurtotic distribution?
I'm familiar with what the 2nd moment (variance) indicates as well as what the 3rd moment (skewness) indicates. I know that on a histogram the 4th moment (kurtosis) indicates the "peeked-ness" of the ...
77
votes
16answers
20k views
Why square the difference instead of taking the absolute value in standard deviation?
In the definition of standard deviation, why do we have to square the difference from the mean to get the mean (E) and take the square root back at the end? Can't we just simply take the absolute ...
14
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6answers
2k views
