Can someone indicate a real life example on how to process an xgb.DMatrix for a regular data file (for xgboost package in R) ?

Hi, I tried processing data in order to get an xgb.DMatrix object, but I ran into difficulties. All examples found in the xgboost package documentation or Xgboost presentation vignette are...

07 August 2018 2,679 6 View

Can anyone direct me to this paper by Noether (1963) A note on the Kolmogorov-Smirnov statistic in the discrete case?

31 December 2015 7,680 5 View

What is your favorite reference econometrics book?

Except for econometricians, most of us usually have one or more books they refer to when we want to get a first-hand reference on some basic or advanced topics, and/or get some basic understanding...

31 December 2013 2,780 5 View

Are there any data-processing routines-scripts available for R?

I need to process some data, nothing fancy, crosstabs, means and medians, and I want to automate it as much as possible. So far I use xtabs and SummaryBy from the doBy library. Do you know if...

04 May 2013 1,907 1 View

Do you know a software that can capture crystal-clear pictures of selected areas of the screen?

I'm writing a book on R and I need a free software that can take crystal-clear pictures of the screen. I use ScreenHunter, but images are not very sharp.

31 December 2012 9,366 0 View

Data Science International Summer School, 17-26 July 2020 Predeal, Romania

01 January 1970 2,332 2 View

How to compare two groups with only two measurements?

Hiiiii everyone! I have an enquiry on statistical analysis. I was looking for many forum and it's still cannot solve my problem. I want to compare means of two groups of data but only with two...

03 March 2021 8,796 3 View

Enhanced Yellow Fluorescent Protein (Aequorea victoria) DNA sequence?

I am on the lookout for the Enhanced Yellow Fluorescent Protein (Aequorea victoria) DNA sequence. Does anyone know where I can find it? Thank you in advance

03 March 2021 3,568 1 View

What kind of fluid could I use for a pitfall trap that also does not invalidate molecular testing?

Hi, I want to start testing pitfall trap to obtain ants samples, but I need to conduct molecular analysis on those insects. So, what kind of fluid can I use? Ethanol expires too early and I need...

03 March 2021 5,978 5 View

What's the best way to measure growth rates in House sparrow chicks from day 2 to day 10?

What's the best way to measure growth rates in House sparrow chicks from day 2 to day 10? Since, the growth curve from day 2 to 10 won't be like the "Logistic curve" it might not follow logistic...

03 March 2021 1,401 3 View

Do we need to write protocol for a second study of a systematic review that has been registered and published?

I have conducted and published a systematic review and meta-analysis research with the topic related to public health and health pomotion (protocol was registed in PROSPERO). Now we want to...

03 March 2021 8,920 3 View

How to increase a model accuracy ?

dear community, my model is based feature extraction from non stationary signals using discrete Wavelet Transform and then using statistical features then machine learning classifiers in order to...

03 March 2021 6,994 5 View

1. What is the impact of having different scales in a survey? and how can we solve this problem before and after data collection (Literature)?

1. What is the impact of having different scales in a survey? and how can we solve this problem before and after data collection (Literature-based reflection)? Thank you for your time and for...

03 March 2021 2,870 3 View

What degree of missing data in a particular case/participant results in Expectation-Maximisation no longer working?

I'm dealing with a mediation model and am using the PROCESS module in SPSS. Due to SPSS and PROCESS being limited in the imputation methods - being unable to handle multiple imputation - the other...

02 March 2021 4,362 1 View

Do I need to do linear regression before running mediation analysis using PROCESS MACRO by Hayes ?

I just wanted to check if I need to run a linear regression separately if I am using PROCESS MACRO to run mediation analysis. Thank you.

02 March 2021 4,359 3 View

Sample dilution for quantitative analysis using ELISA?

If the detection range is in ng/ml but the reference range is in ug/ml for a molecule or protein in serum or plasma .how to dilute and what is the initial volume to be taken for quantitative analysis

02 March 2021 7,670 3 View