Linked Questions

0
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0answers
75 views

Log transformation in R (Precipitation Data) [duplicate]

In many situations the values that a random variable, X, can take on is restricted, for example precipitation data [0,inf), that is f(x) = 0 for x < 0. We say that the support of f(x) is [0,inf). ...
0
votes
0answers
63 views

Kernel density estimation for a variable with lots of zeros [duplicate]

I am trying to estimate the kernel density for number of days a child is sick. Around 73% of children report not being sick, i.e. zero. How do I estimate a kernel density for this censored variable ...
0
votes
0answers
30 views

Non-Parametric Density estimation with a positive variable [duplicate]

I’m struggling to find a way to represent a kernel density estimation with a nonnegative random variable. I have read a couple of articles tackling this issue; however I couldn’t implement it in R. I ...
10
votes
4answers
2k views

How can I estimate the density of a zero-inflated parameter in R?

I have a data set with lots of zeros that looks like this: set.seed(1) x <- c(rlnorm(100),rep(0,50)) hist(x,probability=TRUE,breaks = 25) I would like to draw ...
0
votes
1answer
6k views

“Negative density” for non-negative variables [closed]

Having an integer positive variable (number of days) in an experiment, I got negative values for the kernel density plots using R. I have read other posts relating to this topic. They admitted that ...
10
votes
2answers
1k views

Kernel density estimation on asymmetric distributions

Let $\{x_1,\ldots,x_N\}$ be observations drawn from an unknown (but certainly asymmetric) probability distribution. I would like to find the probability distribution by using the KDE approach: $$ \...
1
vote
2answers
3k views

Does this graph follow a exponential distribution or a log-normal?

command for the graph: hist(c1,freq=FALSE) lines(density(c1,adjust=2),col="darkblue",lwd=2) I generated this sequence in R: ...
1
vote
1answer
1k views

Why simulated gamma distributed data have negative kernel values?

I know that Gamma distribution does not allow 0 or negative values. I was doing some simulation and when I write this code in R ...
4
votes
3answers
298 views

Information loss by histograms

Recently I became curious about what I imagine to be an old problem: the fidelity of histograms to an underlying data set. CrossValidated has a number of questions on the subject of "optimal ...
1
vote
0answers
204 views

Weighted density estimation of exponentially distributed RV [closed]

I am trying to get a weighted density estimation of some data. Unfortunately, the data is approximately exponentially distributed after the weight transform, which gives a false sense of positive ...
1
vote
0answers
146 views

strange density plot of p-value [duplicate]

I computed the T-score and P-value using t.test() for my data, and finally I've plotted the density of my p-value and I've got strange plot. I don't know, why I see ...
1
vote
1answer
103 views

downsampling a kde / combining kde and histogram

I'm calculating a KDE of one parameter (y, particle density) in bins of another parameter (x, distance from the origin). At ...
1
vote
0answers
94 views

Can kernel density estimation be used to estimate a radial probability density?

I am trying to estimate the PDF of the radius of points distributed in a 2D plane. The points are distributed like this: I can produce a histogram of the radius data which looks like this: I want ...
1
vote
1answer
59 views

Why density plot tails are beyond maximum and minimum values?

I am trying to interpret the tails of a density curve, which go beyond xlims(0 in this case). I understand that area under the curve between any two points represents the probability of that event. ...
1
vote
0answers
47 views

Computationally cheap estimation of the mode from 2D samples

I say 'mode' in the title – perhaps there's something more appropriate I can find. Here's my problem: A person is in a $100\mathrm m$ by $500\mathrm m$ space. I have about 100 samples randomly ...

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