Linked Questions

11
votes
2answers
9k views

How to plot binary (presence/absence - 1/0) data against continuous variables [duplicate]

I am trying to plot presence/absence (1/0) of a sample species against various environmental variables. I have put presence/absence on the y-axis and the environmental variable (in this case ...
295
votes
10answers
284k views

Difference between logit and probit models

What is the difference between Logit and Probit model? I'm more interested here in knowing when to use logistic regression, and when to use Probit. If there is any literature which defines it using ...
36
votes
2answers
82k views

Interpretation of R's output for binomial regression

I'm quite new on this with binomial data tests, but needed to do one and now I´m not sure how to interpret the outcome. The y-variable, the response variable, is binomial and the explanatory factors ...
29
votes
3answers
23k views

Interpretation of simple predictions to odds ratios in logistic regression

I'm somewhat new to using logistic regression, and a bit confused by a discrepancy between my interpretations of the following values which I thought would be the same: exponentiated beta values ...
17
votes
3answers
15k views

How to present box plot with an extreme outlier?

I could use some guidance about presenting some data. This first plot is a case-control comparison for the cytokine IL-10. I've manually set the y axis to include 99% of the data. The reason I set ...
13
votes
4answers
2k views

Graphing small samples

I have a small data set of 14 separate times to complete a task. However I am having difficulty finding an appropriate graph to use to graph the data. If the sample was larger I would use a box plot ...
12
votes
3answers
3k views

ROC curve crossing the diagonal

I am running a binary classifier at the moment. When I plot the ROC curve I get a good lift at the beginning then it changes direction and crosses the diagonal then of course back up, making the curve ...
6
votes
4answers
3k views

When does logistic regression not work properly?

I need to find a situation in which logistic regression does not work well. Furthermore, I would like to know when a random forest might perform better than a logistic regression model.
4
votes
1answer
7k views

Minimum “recommended” sample size for boxplots? Boxplots for different sample sizes

What is the minimum "recommended" sample size to generate boxplots? If I'm comparing different methods and each method has a different sample size, is it fine to use boxplots for this comparison? If ...
3
votes
2answers
2k views

Understanding lack of fit in logistic regression

How does one interpret the fact that a dataset has a poor fit / lack of fit with respect to a logistic regression model? I can make sense, for example, of a lack of fit in the case of a linear ...
4
votes
2answers
853 views

Approaches for comparing visual representation of two distributions with unequal sample sizes

I have two distributions of continuous, unpaired measurements. I would like to visualize the two distributions with a pair of histograms, counting measurements that fall over a bin's interval. Are ...
2
votes
1answer
3k views

How to calculate total error of decision tree

If have a decision tree, say with two leaves, how do I calculate the total error? One can calculate the error for each leaf, but is the total error the sum of the errors or the product (or neither)?
1
vote
1answer
2k views

Should predicted probabilities from Logistic Regression correspond with percentages?

I have conducted a logistic regression in order to identify whether student status (student/non-student), time period (time 1, 2 or 3), or condition (condition 1 or condition 2) predict a binary ...
1
vote
2answers
641 views

Histogram or box plot, to compare two distributions of means?

I've got two different distributions of participant reaction time means (20 data points for condition A, another 20 for condition B). I'm stuck trying to decide between using a histogram, or a box ...
4
votes
1answer
449 views

u-shape for logistic regression?

I'm stuck and have real problems what to interpret from my current results. Maybe you can help me out? Thanks! Lets say... I'm investigating on the influence of health factors on dying. Dependent ...

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