Tag / r language
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Is there a relationship between teacher salary and their student’s SAT scores?
Among some of the amazing talks from Cognitive Systems Institute Group Speaker Series, one of the most wonderful is the talk made by Mine Cetinkaya-Rundel about “Teaching Data Science”. One of the examples presented by her was about the salary teachers and the relationship with the SAT. In this very simple example, we can apply linear regression,…
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How to show correlations between variables?
When we work with linear regression we need to understand the relationship between the variables, that is, which variables depend on others, for this we analyze the correlation between the different variables that make up our dataset. Below is an example using ggally one of the many libraries that allow us to perform this analysis…
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How to create a Heatmap (II): heatmap or geom_tile
Heatmaps visualise data through variations in colouring. There are different functions to create a heatmap, one of them is using the heatmap function, but it is also possible to create a heatmap using geom_tile from ggplot2. The election for one of these function relies on the dataset. Below there is an example developed step by…
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How to create a heatmap (Updated!)
A heatmap is basically a table that has colors in place of numbers. Colors correspond to the level of the measurement. Each column can be a different metric like above. It’s useful for finding highs and lows and sometimes, patterns. From Nathan Yau | Visualize This One of the problems when we have a…
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Deep learning: Neural network
Vamos a implementar una red neuronal utilizada para prediccion de valores. Idea Vamos a trabajar para poder predecir la fortaleza del concreto, si bien es un material amplisimamente utilizado, debido a que esta compuesto por una gran cantidad de materiales es dificil precedir su fortaleza en el producto final. El objetivo es predecir la fortaleza…
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Multiple lineal regression (II) Improving the model
En este post empezamos a trabajar con linear regression, en esta segunda parte vamos a trabajar para mejorar la performance de nuestro modelo, principalmente agregando relaciones entre variables. Mejorando el modelo Vamos a agregar tres nuevas relaciones a traves de la creacion de tres nuevas variables en nuestro dataset: Cambio de la variable edad de…
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Multiple lineal regression (I)
Cuando hablamos de modelos de regresion estamos hablando acerca de analizar relaciones entre variables numericas. Que es regresion? es entender las relaciones entre una variable dependiente (que sera el valor a ser predecido) y una o mas variables independientes (las variables predictoras). La forma mas simple de regresion asume una relacion lineal entre una variable…
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Divide and conquer(II) : classification rules
Classification rules representa conocimiento en forma de afirmaciones sencillas de si y no, de forma de poder asignarle una clase a ejemplos que no tienen una clasificacion (todavia). Rule learners son usados de forma similar a los arboles de desicion, de la misma forma que los arboles de desicion permiten ver como se estan estableciendo…
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Divide and conquer(I) : classification using desicion trees
En este post me gustaria desarrollar otros de los algoritmos necesarios para trabajar en problemas que impliquen clasificacion: desicion trees y Rule Learners los cuales permiten transformar desiciones complejas en un set de opciones simples. Desicion trees Tal vez una de las tecnicas mas utilizada de machine learning, aplicable a casi cualquier tipo de datos…
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Naive Bayes Algorithm
Naive Bayes – a Not so Naive Algorithm Naive Bayes algorithm is called Naive because the algorithm makes a very strong assumption about the data having features independent of each other while in reality, they may be dependent in some way. Assumes that the presence of one feature in a class is completely unrelated to…
