Publications by Donny Lofland
Data 621 - Assignment 1 - Moneyball
Source code: https://github.com/djlofland/DS621_F2020_Group3/tree/master/Homework_1 Overview In professional sports, there is a huge interest in attempting to leverage historic statistics to both predict future outcomes (wins/losses) and explore opportunities for tuning or improving a team or individual’s performance. This data-driven approach...
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DATA 624 - Homework 2 (Forecasting)
Problem 3.1 For the following series, find an appropriate Box-Cox transformation in order to stabilise the variance. usnetelec autoplot(usnetelec) (lambda1 <- BoxCox.lambda(usnetelec)) ## [1] 0.5167714 autoplot(BoxCox(usnetelec, lambda1)) We notice in the original plot, there is a slight exponential increase in the values over time. pplying a...
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DATA 624 - Homework 3 (TS Decomposition)
DS624 Homework 3 Problem 6.2 The plastics data set consists of the monthly sales (in thousands) of product A for a plastics manufacturer for five years. Plot the time series of sales of product A. Can you identify seasonal fluctuations and/or a trend-cycle? autoplot(plastics, xlab="Time (year)", ylab = 'Monthly Sales (thousands)') Overall the...
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DATA 621 - Assignment 2 - Cllassification Metrics
Source code: https://github.com/djlofland/DS621_F2020_Group3/tree/master/Homework_2 Overview This assignment will present various classification metrics through creating functions in R that will carry out these calculations. These calculations will be will be compared against built-in functions from various R packages and a graphical representat...
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DATA 624 - Homework 4 (Data Processing)
Source Code: https://github.com/djlofland/DATA624_PredictiveAnalytics/tree/master/Homework_4 Problem 3.1 The UC Irvine Machine Learning Repository6 contains a data set related to glass identification. The data consist of 214 glass samples labeled as one of seven class categories. There are nine predictors, including the refractive index and perc...
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DATA 624 Homework 6 (ARIMA)
Source Code: https://github.com/djlofland/DATA624_PredictiveAnalytics/tree/master/Homework_6 Problem 8.1 Figure 8.31 shows the ACFs for 36 random numbers, 360 random numbers and 1,000 random numbers. Explain the differences among these figures. Do they all indicate that the data are white noise? Problem 8.1 ACF Graphs ACF looks for correlatio...
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Bimodal Feature Extraction
Overview Bimodal features in a dataset are both problematic, interesting, and potentially an area of opportunity and exploration. Bimodal data suggests that there are possibly two different subgroups or classes being observed within the feature. I will be using the classic Moneyball dataset and the TEAM_BATTING_SO feature to illustrate. Load Sam...
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Impact of Random Sampling on AB Tests KPI’s
Overview In the business world, it’s common to run AB Tests, or Split Tests, to help understand the impact of making changes to a given feature, marketing campaign, website, etc. When performing AB test, we usually randomly assign users to one of two group, each getting a different treatment. We then collect data over some period of time then c...
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Data 621 - Homework 4 (Wine Regression)
Source code: https://github.com/djlofland/DS621_F2020_Group3/tree/master/Homework_5 Overview The wine dataset is a highly popular one in the data science community, as it models some of the challenges of real world datasets and can be modeled by a variety of different model types. We will first explore the data looking for issues or challenges (...
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DS624-Project2
Source code: https://github.com/djlofland/DATA624_F2020_Group/tree/master/ Instructions Overview This is role playing. I am your new boss. I am in charge of production at ABC Beverage and you are a team of data scientists reporting to me. My leadership has told me that new regulations are requiring us to understand our manufacturing process, th...
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