linear regression analysis
while A.3 is a common assumption in linear regression analysis and it relates to the LARS problem in our online
We thank all the reviewers for carefully reading of the manuscript and constructive comments. Reviewer #1: Assumptions A.2 and A.3 used in Algorithm 2. Reviewer #3: There seem to be several misunderstandings regarding the steps of our algorithm and its analysis. To maintain the list constant, for every added point another point is removed.
- Research Report > New Finding (0.52)
- Research Report > Experimental Study (0.41)
Identifying Factors to Help Improve Existing Decomposition-Based PMI Estimation Methods
Nau, Anna-Maria, Ditto, Phillip, Steadman, Dawnie Wolfe, Mockus, Audris
Accurately assessing the postmortem interval (PMI) is an important task in forensic science. Some of the existing techniques use regression models that use a decomposition score to predict the PMI or accumulated degree days (ADD), however, the provided formulas are based on very small samples and the accuracy is low. With the advent of Big Data, much larger samples can be used to improve PMI estimation methods. We, therefore, aim to investigate ways to improve PMI prediction accuracy by (a) using a much larger sample size, (b) employing more advanced linear models, and (c) enhancing models with factors known to affect the human decay process. Specifically, this study involved the curation of a sample of 249 human subjects from a large-scale decomposition dataset, followed by evaluating pre-existing PMI/ADD formulas and fitting increasingly sophisticated models to estimate the PMI/ADD. Results showed that including the total decomposition score (TDS), demographic factors (age, biological sex, and BMI), and weather-related factors (season of discovery, temperature history, and humidity history) increased the accuracy of the PMI/ADD models. Furthermore, the best performing PMI estimation model using the TDS, demographic, and weather-related features as predictors resulted in an adjusted R-squared of 0.34 and an RMSE of 0.95. It had a 7% lower RMSE than a model using only the TDS to predict the PMI and a 48% lower RMSE than the pre-existing PMI formula. The best ADD estimation model, also using the TDS, demographic, and weather-related features as predictors, resulted in an adjusted R-squared of 0.52 and an RMSE of 0.89. It had an 11% lower RMSE than the model using only the TDS to predict the ADD and a 52% lower RMSE than the pre-existing ADD formula. This work demonstrates the need (and way) to incorporate demographic and environmental factors into PMI/ADD estimation models.
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- Research Report > New Finding (1.00)
- Research Report > Experimental Study (1.00)
3 methods to deal with outliers
An outlier is a data point that is distant from other similar points. They may be due to variability in the measurement or may indicate experimental errors. If possible, outliers should be excluded from the data set. However, detecting that anomalous instances might be very difficult, and is not always possible. Machine learning algorithms are very sensitive to the range and distribution of attribute values.
3 methods to deal with outliers
An outlier is a data point that is distant from other similar points. They may be due to variability in the measurement or may indicate experimental errors. If possible, outliers should be excluded from the data set. However, detecting that anomalous instances might be very difficult, and is not always possible. Machine learning algorithms are very sensitive to the range and distribution of attribute values.
3 methods to deal with outliers
An outlier is a data point that is distant from other similar points. They may be due to variability in the measurement or may indicate experimental errors. If possible, outliers should be excluded from the data set. However, detecting that anomalous instances might be very difficult, and is not always possible. Machine learning algorithms are very sensitive to the range and distribution of attribute values.
Linear Regression Analysis using R – Step Up Analytics
One of the most frequent used techniques in statistics is linear regression where we investigate the potential relationship between a variable of interest (often called the response variable but there are many other names in use) and a set of one of more variables (known as the independent variables or some other term). Unsurprisingly there are flexible facilities inR for fitting a range of linear models from the simple case of a single variable to more complex relationships. In this post we will consider the case of simple linear regression with one response variable and a single independent variable. The purpose of using this data is to determine whether there is a relationship, described by a simple linear regression model, between variables. You seen in the image that first i checked my working directory and then changed it to another directory, this means the working datafiles have another location so i changed it for my help.
- Research Report > New Finding (0.40)
- Research Report > Experimental Study (0.40)
Assessing the Quality of Learned Local Models
Schaal, Stefan, Atkeson, Christopher G.
An approach is presented to learning high dimensional functions in the case where the learning algorithm can affect the generation of new data. A local modeling algorithm, locally weighted regression, is used to represent the learned function. Architectural parameters of the approach, such as distance metrics, are also localized and become a function of the query point instead of being global. Statistical tests are given for when a local model is good enough and sampling should be moved to a new area. Our methods explicitly deal with the case where prediction accuracy requirements exist during exploration: By gradually shifting a "center of exploration" and controlling the speed of the shift with local prediction accuracy, a goal-directed exploration of state space takes place along the fringes of the current data support until the task goal is achieved.
- North America > United States > Massachusetts > Middlesex County > Cambridge (0.14)
- North America > United States > New York > New York County > New York City (0.04)
- North America > United States > California > San Mateo County > Redwood City (0.04)
Assessing the Quality of Learned Local Models
Schaal, Stefan, Atkeson, Christopher G.
An approach is presented to learning high dimensional functions in the case where the learning algorithm can affect the generation of new data. A local modeling algorithm, locally weighted regression, is used to represent the learned function. Architectural parameters of the approach, such as distance metrics, are also localized and become a function of the query point instead of being global. Statistical tests are given for when a local model is good enough and sampling should be moved to a new area. Our methods explicitly deal with the case where prediction accuracy requirements exist during exploration: By gradually shifting a "center of exploration" and controlling the speed of the shift with local prediction accuracy, a goal-directed exploration of state space takes place along the fringes of the current data support until the task goal is achieved.
- North America > United States > Massachusetts > Middlesex County > Cambridge (0.14)
- North America > United States > New York > New York County > New York City (0.04)
- North America > United States > California > San Mateo County > Redwood City (0.04)
Assessing the Quality of Learned Local Models
Schaal, Stefan, Atkeson, Christopher G.
An approach is presented to learning high dimensional functions in the case where the learning algorithm can affect the generation of new data. A local modeling algorithm, locally weighted regression, is used to represent the learned function. Architectural parameters of the approach, such as distance metrics, are also localized and become a function of the query point instead of being global. Statistical tests are given for when a local model is good enough and sampling should be moved to a new area. Our methods explicitly deal with the case where prediction accuracy requirements exist during exploration: By gradually shifting a "center of exploration" and controlling the speed of the shift with local prediction accuracy,a goal-directed exploration of state space takes place along the fringes of the current data support until the task goal is achieved.
- North America > United States > Massachusetts > Middlesex County > Cambridge (0.14)
- North America > United States > New York > New York County > New York City (0.04)
- North America > United States > California > San Mateo County > Redwood City (0.04)