Articles by Al-Ahmadgaid Asaad

Measures of Skewness and Kurtosis

June 10, 2013 | Al-Ahmadgaid Asaad

Skewness and kurtosis in R are available in the moments package (to install an R package, click here), and these are:Skewness - skewnessKurtosis - kurtosisExample 1. Mirra is interested in the elapse time (in minutes) she spends on riding a tricycle fr... [Read more...]

Measure of Relative Variability

June 10, 2013 | Al-Ahmadgaid Asaad

The measure of relative variability is the coefficient of variation (CV). Unlike measures of absolute variability, the CV is unitless when it comes to comparisons between the dispersions of two distributions of different units of measurement. In R, CV ... [Read more...]

Measures of Absolute Variability

June 10, 2013 | Al-Ahmadgaid Asaad

Measures of absolute variability deal with the dispersion of the data points. This include the following:Range - rangeInterquartile Range - IQRQuartile DeviationAverage DeviationStandard Deviation - sdThese measures of variability restrict to uniform u... [Read more...]

Quartiles, Deciles, and Percentiles

June 9, 2013 | Al-Ahmadgaid Asaad

The measures of position such as quartiles, deciles, and percentiles are available in quantile function. This function has a usage,where:x - the data pointsprob - the location to measurena.rm - if FALSE, NA (Not Available) data points are not ignoredna... [Read more...]

Mean and Median

June 8, 2013 | Al-Ahmadgaid Asaad

Mean in R is computed using the function mean. Consider the scores of 20 MSU-IIT students in Stat 101 exam with a hundred items: 70, 78, 66, 65, 50, 53, 48, 88, 95, 80, 85, 84, 81, 63, 68, 73, 75, 84, 49, and 77. Compute and interpret the mean and medi... [Read more...]

Matrix Operations

June 8, 2013 | Al-Ahmadgaid Asaad

Matrix manipulation in R are very useful in Linear Algebra. Below are lists of common yet important functions in dealing operations with matrices:Transpose - tMultiplication - %*%Determinant - detInverse - solve, or ginv of MASS libraryEigenvalues and ... [Read more...]

Data Class Conversion

June 6, 2013 | Al-Ahmadgaid Asaad

Data in R can be converted from one class to the other. The function is prefixed with as. then followed by the name of the data class that we wish to convert to. Data class in R are the following:numeric - as.numericvector - as.vectorcharacter - as.cha... [Read more...]

Inputting Data in Matrix Format

June 6, 2013 | Al-Ahmadgaid Asaad

Matrix in R is formed using matrix, rbind, or cbind function. These functions have the following descriptions:matrix - used to transform a concatenated data into matrix form of compatible dimensions. rbind - short for row bind, that binds a conca... [Read more...]

Importing Data to R

March 30, 2013 | Al-Ahmadgaid Asaad

There are number of ways in importing data into R, and several formats are available,From Excel to R From SPSS to RFrom Stata to R, and more hereIn this post, I'm going to talk about importing common data format that we often encounter, such as Excel, ... [Read more...]

Entering Data to R

March 30, 2013 | Al-Ahmadgaid Asaad

To enter data into R, two common and easy to use R functions are utilized.The concatenate function, c; and,The data.frame function.The concatenate function, c, is use for combining data points into a single numeric R object. The usage of this function ... [Read more...]

Download and Install R in Ubuntu

March 30, 2013 | Al-Ahmadgaid Asaad

There are two ways to install R in Ubuntu. One is through the terminal, and the other is through the Ubuntu Software Center.Through TerminalPress Ctrl+Alt+T to open Terminal Then execute sudo apt-get update After that, sudo apt-get install r-baseT... [Read more...]

Download and Install R in Windows

March 30, 2013 | Al-Ahmadgaid Asaad

The R statistical package is available at CRAN website. In this site, do the followingClick the Download R for Windows. Then go to install R for the first time in the base subdirectory. And finally download the latest version of R for windows... [Read more...]

Experimental Design: Problem Set

June 21, 2012 | Al-Ahmadgaid Asaad

QUESTIONSThe tensile strength of Portland cement is being studied. Four different mixing techniques can be used economically. The following data have been collected: MixingTechniques Tensile Strength (lb/in­­2) 1 3129 3000 2865 2890 2 3200 3300 2975 3150 3 2800 2900 3985 3050 4 2600 2700 2600 2765 Test the hypothesis that mixing techniques affect the strength of the cement. Use $\alpha=0.05$.Construct a graphical display as described in Section 3...
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My On-Job Training Analytics

May 22, 2012 | Al-Ahmadgaid Asaad

I have been working at Provincial Statistics Office of Tawi-Tawi (Philippines) which was part of the training on my OJT (On-Job Training). One of the requirements of the training is at least 80 hours of services, so I decided to work from April 19 to M...
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