1688 search results for "time series"

Example 7.32: Add reference lines to a plot; fine control of tick marks

April 12, 2010
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Example 7.32: Add reference lines to a plot; fine control of tick marks

Sometimes it's useful to plot regular reference lines along with the data. For a time-series plot, this can show when critical values are reached in a clearer way than simple tick marks.As an example, we revisit the empirical CDF plot shown in Example...

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How to Produce Fake Data Analysis in R: 3 Easy Steps

April 2, 2010
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How to Produce Fake Data Analysis in R: 3 Easy Steps

Did you really think that a team of researchers spent their weekends counting the number of shirtless adolescent men and exposed penises they could find on charoulette.com? Perhaps you should not answer that, as it may be a better measure of your opinion of sociologist than gullibility. It is true, sociologist do say the

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Summarising data using dot plots

March 26, 2010
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Summarising data using dot plots

A dot plot is a type of display that compares counts, frequencies, totals or other summary measures for a series of categories. The dot plot can be arranged with the categories either on the vertical or horizontal axis of the display to allow comparising between the different categories as well as comparison within categories where

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ggplot2: Changing the Default Order of Legend Labels and Stacking of Data

March 23, 2010
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ggplot2: Changing the Default Order of Legend Labels and Stacking of Data

“How to change the order of legend labels” is a question that gets asked relatively often on ggplot2 mailing list. A variation of this question is how to change the order of series in stacked bar/lineplots. While these two questions seem to be related, in fact they are separate as the legend is controlled by

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Happy Anniversary NYC R Meetup

March 12, 2010
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Happy Anniversary NYC R Meetup

Today is the one year anniversary of the NYC R Statistical Meetup. Starting as a small group meeting in a crowded conference room, Josh Reich established the meetup as the premiere gathering of data geeks in the tri-state area. Over the past year we have had 10 meetups, and two more upcoming on the

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Visualizing Drought

March 6, 2010
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Visualizing Drought

The impacts of drought depend on time-scale. On short time-scales, drought means dry soil. On long time-scales, it means dry rivers and empty reservoirs. A region may simultaneously experience dry conditions on one time-scale and wet conditions on another e.g. wet soil but low streamflow or visa versa. Standardized Precipitation Index (SPI) is a widely

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ggplot2: Plotting Dates, Hours and Minutes

February 24, 2010
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ggplot2: Plotting Dates, Hours and Minutes

Plotting timeseries with dates on x-axis and times on y-axis can be a bit tricky in ggplot2. However, with a little trick this problem can be easily overcome. Let’s assume that I wanted to plot when the sun rises in London in 2010. sunriset function in maptools package calculates the sunrise times using algorithms provided

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The R type system

February 21, 2010
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The R type system

R is a weird beast. Through it's ancestor the S language, it claims a proud heritage reaching back to Bell Labs in the 1970's when S was created as an interactive wrapper around a set of statistical and numerical subroutines. As a programming language,...

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Genetic Algorithm Systematic Trading Development — Part 3 (Python/VBA)

February 20, 2010
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Genetic Algorithm Systematic Trading Development — Part 3  (Python/VBA)

As mentioned in prior posts, it is not possible to use the standard Weka GUI to instantiate a Genetic Algorithm, other than for feature selection. Part of the reason is that there is no generic algorithm to instantiate a fitness function. The same fl...

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Generalized linear mixed effect model problem

February 16, 2010
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Generalized linear mixed effect model problem

I am trying to compare cohort difference in infant mortality using generalized linear mixed model. I first estimated the model in Stata:xi:xtlogit inftmort i.cohort, i(code)which converged nicely:Fitting comparison model:Iteration 0:   log likelih...

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