Posts Tagged ‘ R functions ’

Teach Yourself How to Create Functions in R

February 1, 2011
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Teach Yourself How to Create Functions in R

As you can tell from my previous posts, I am diving in head first into learning how to program (and simplify) my analytical life using R.  I have always learned by example and have never really prospered from the “learn from scratch” school of thought.  As I follow along with some other fellow R programmers,

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Clustergram: visualization and diagnostics for cluster analysis (R code)

June 15, 2010
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Clustergram: visualization and diagnostics for cluster analysis (R code)

About Clustergrams In 2002, Matthias Schonlau published in “The Stata Journal” an article named “The Clustergram: A graph for visualizing hierarchical and . As explained in the abstract: In hierarchical cluster analysis dendrogram graphs are used to visualize how clusters are formed. I propose an alternative graph named “clustergram” to examine how cluster members are assigned to clusters as...

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Geometric and harmonic means in R

July 20, 2009
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Geometric and harmonic means in R

Compute the geometric mean and harmonic mean in R of this sequence.10, 2, 19, 24, 6, 23, 47, 24, 54, 77These features are not present in the standard package of R, although they are easily available in some packets. However, it is easy to calculate the...

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Probability exercise: negative binomial distribution

July 19, 2009
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Probability exercise: negative binomial distribution

What is the probability you get the 4th cross before the 3rd head, flipping a coin?The mathematical formula for solving this exercise, which follows a negative binomial distribution, is:$$f(x)=P(X=x)=\begin{pmatrix} x+y-1\\ y-1 \end{pmatrix} \cdot p^x ...

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A probability exercise on the Bernoulli distribution

July 18, 2009
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A probability exercise on the Bernoulli distribution

What is the probability, flipping a coin 8 times, to obtain the sequence HHTTTHTT? (H = head; T= tail)The theory teaches us that to solve this question, we can simply use the following formula:$$f(x)=P(X=x)=B(n,p)=\begin{pmatrix}n\\ x \end{pmatrix} \cd...

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Let us practice with some functions of R

July 18, 2009
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Let us practice with some functions of R

Given the following data set, compute the arithmetic mean, median, variance, standard deviation; find the greatest and the smaller value, the sum of all values, the square of the sum of all values, the sum of the square of all values; assigne the ranks...

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