All Questions
Tagged with figures or data-visualization
425 questions
247
votes
5
answers
528k
views
How to interpret a QQ plot?
I am working with a small dataset (21 observations) and have the following normal QQ plot in R:
Seeing that the plot does not support normality, what could I infer about the underlying distribution? ...
- 21.1k
120
votes
4
answers
39k
views
Assessing approximate distribution of data based on a histogram
Suppose I want to see whether my data is exponential based on a histogram (i.e. skewed to the right).
Depending on how I group or bin the data, I can get wildly different histograms.
One set of ...
- 1,201
104
votes
1
answer
92k
views
Interpreting plot.lm()
I had a question about interpreting the graphs generated by plot(lm) in R. I was wondering if you guys could tell me how to interpret the scale-location and leverage-residual plots? Any comments ...
- 1,041
89
votes
4
answers
35k
views
How to visualize what canonical correlation analysis does (in comparison to what principal component analysis does)?
Canonical correlation analysis (CCA) is a technique related to principal component analysis (PCA). While it is easy to teach PCA or linear regression using a scatter plot (see a few thousand examples ...
- 993
54
votes
3
answers
95k
views
Suppression effect in regression: definition and visual explanation/depiction
What is a suppressor variable in multiple regression and what might be the ways to display suppression effect visually (its mechanics or its evidence in results)? I'd like to invite everybody who has ...
- 58.8k
63
votes
7
answers
70k
views
Graph for relationship between two ordinal variables
What is an appropriate graph to illustrate the relationship between two ordinal variables?
A few options I can think of:
Scatter plot with added random jitter to stop points hiding each other. ...
43
votes
2
answers
76k
views
Interpretation of plot (glm.model)
Can anyone tell me how to interpret the 'residuals vs fitted', 'normal q-q', 'scale-location', and 'residuals vs leverage' plots? I am fitting a binomial GLM, saving it and then plotting it.
- 531
35
votes
2
answers
15k
views
Is there a boxplot variant for Poisson distributed data?
I'd like to know if there is a boxplot variant adapted to Poisson distributed data (or possibly other distributions)?
With a Gaussian distribution, whiskers placed at L = Q1 - 1.5 IQR and U = Q3 + 1....
- 535
35
votes
3
answers
32k
views
What distribution does my data follow?
Let us say that I have 1000 components and I have been collecting data on how many times these log a failure and each time they logged a failure, I am also keeping track of how long it took my team to ...
- 4,552
7
votes
2
answers
7k
views
How to use boxplots to find the point where values are more likely to come from different conditions?
I have plotted some data using box plots.
I am comparing Condition 1 (left) and Condition 2 (Right) values. My aim is to find a point at which we make a decision where the value changes from point ...
- 151
56
votes
2
answers
76k
views
PP-plots vs. QQ-plots
What is the difference between probability plots, PP-plots and QQ-plots when trying to analyse a fitted distribution to data?
- 691
32
votes
7
answers
17k
views
What are good data visualization techniques to compare distributions?
I am writing my PhD thesis and I've realized that I rely excessively in box plots in order to compare distributions. Which other alternatives do you like for achieving this task?
I'd also like to ask ...
11
votes
3
answers
10k
views
Transfer function in forecasting models - interpretation
I am occupied with ARIMA modelling augmented with exogenous variables for promotional modelling purposes and i have hard time explaining it to business users. In some cases software packages end up ...
- 891
35
votes
2
answers
53k
views
What does an Added Variable Plot (Partial Regression Plot) explain in a multiple regression?
I have a model of Movies dataset and I used the regression:
...
33
votes
5
answers
39k
views
Which is the best visualization for contingency tables?
Which is best plot, from statistical standpoint, to show a contingency table, which is typically being analyzed by chi-square test? Is it a dodged barplot, stacked barplot, heatmap, contour plot, ...
- 10.2k
58
votes
4
answers
127k
views
How to visualize a fitted multiple regression model?
I am currently writing a paper with several multiple regression analyses. While visualizing univariate linear regression is easy via scatter plots, I was wondering whether there is any good way to ...
- 1,435
43
votes
3
answers
97k
views
What test can I use to compare slopes from two or more regression models?
I would like to test the difference in response of two variables to one predictor. Here is a minimal reproducible example.
...
- 3,901
36
votes
3
answers
4k
views
Datasets constructed for a purpose similar to that of Anscombe's quartet
I've just come across Anscombe's quartet (four datasets that have almost indistinguishable descriptive statistics but look very different when plotted) and I am curious if there are other more or less ...
33
votes
3
answers
13k
views
Visualizing a million, PCA edition
Is it possible to visualize the output of Principal Component Analysis in ways that give more insight than just summary tables? Is it possible to do it when the number of observations is large, say ~...
- 5,640
4
votes
2
answers
4k
views
Can I analyze or model a conditional correlation?
In my research I'm looking at the correlation between self-harm and aggression (both continuous). Now, I also have some variables (e.g. depressive symptoms; also continuous) which I do believe ...
- 41
5
votes
1
answer
5k
views
How to interpret schoenfield residual plot
I used the veteran database of the package "survival" to do survival analysis. I tried to check the proportional hazard assumption, with with schoenfied residual plot. I always thought if we ...
- 939
31
votes
4
answers
7k
views
Visualising many variables in one plot
I'd like to show how the values of certain variables (~ 15) change over time, but I'd also like to show how the variables differ from each other in each year. So I created this plot:
But even when ...
user45065
14
votes
4
answers
94k
views
How to visualize independent two sample t-test?
What are the most accepted ways to visualize the results of an independent two sample t-test? Is a numeric table more often used or some sort of plot? The goal is for a casual observer to look at the ...
- 141
37
votes
2
answers
90k
views
Interpretation of biplots in principal components analysis
I came across this nice tutorial: A Handbook of Statistical Analyses Using R. Chapter 13. Principal Component Analysis: The
Olympic Heptathlon on how to do PCA in R language. I don't understand the ...
- 2,799
22
votes
1
answer
2k
views
Diagnostic plot for assessing homogeneity of variance-covariance matrices
Is there a handy plot for comparing the variance-covariance matrices of two (or perhaps more) groups? An alternative to looking at lots of marginal plots, especially in the multivariate Normal case?
- 31.6k
15
votes
5
answers
3k
views
Removing extraneous points near the centre of a QQ-plot
I'm trying to plot a QQ-plot with two data sets of about 1.2 million points, in R (using qqplot, and feeding the data into ggplot2). The calculation is easy enough, but the resulting graph is ...
- 5,541
15
votes
2
answers
23k
views
Box-and-Whisker Plot for Multimodal Distribution
Can I use box-and-whisker plots also for multimodal distribution or only for unimodal distribution?
- 253
6
votes
3
answers
3k
views
How to plot a learning curve based on a sequence of date stamped successes and failures?
I have data on results of surgical operations:
date of operation (in YYYY-MM-DD format)
result of operation (0 for successful operation, 1 for unsuccessful operation)
Date is usually used only for ...
- 4,139
62
votes
12
answers
21k
views
Software needed to scrape data from graph [closed]
Anybody have any experience with software (preferably free, preferably open source) that will take an image of data plotted on cartesian coordinates (a standard, everyday plot) and extract the ...
27
votes
3
answers
13k
views
Visualizing Likert Item Response Data
What are good ways to visualize set of Likert responses?
For example, a set of items inquiring about the importance of X to one's decisions about A, B, C, D, E, F & G? Is there something better ...
alex hoffman
18
votes
2
answers
20k
views
QQ plot does not match histogram
I have a histogram, kernel density and a fitted normal distribution of financial log returns, which are transformed into losses (signs are changed), and a normal QQ plot of these data:
The QQ plot ...
- 2,339
10
votes
2
answers
5k
views
How to represent kWh usage by year against average temperature?
Just for fun, I want to chart my monthly household power consumption year-over-year. However, I wish to include some reference to monthly temperature so I can determine if my home or behavior is ...
- 203
57
votes
6
answers
82k
views
How to determine best cutoff point and its confidence interval using ROC curve in R?
I have the data of a test that could be used to distinguish normal and tumor cells. According to ROC curve it looks good for this purpose (area under curve is 0.9):
My questions are:
How to ...
- 4,139
54
votes
5
answers
317k
views
R - QQPlot: how to see whether data are normally distributed
I have plotted this after I did a Shapiro-Wilk normality test. The test showed that it is likely that the population is normally distributed. However, how to see this "behaviour" on this plot?
...
- 3,729
20
votes
4
answers
29k
views
Visualizing Likert responses using R or SPSS
I have 82 respondents in 2 groups (43 in Group A and 39 in Group B) that completed a survey of 65 Likert questions each ranging from 1 – 5 (strongly agree - strongly disagree). I therefore have a ...
- 351
18
votes
2
answers
7k
views
Alternative to sieve / mosaic plots for contingency tables
I once stumbled across a type of plot for categorical data (i.e., contingency tables) on the internet, which I really liked, but I've never found it again, and I don't even know what it's called. It ...
17
votes
1
answer
1k
views
Source for inter-ocular trauma test for significance
TL;DR: I am looking for the paper that proposed the following "inter-ocular trauma test for statistical significance".
Longer version
The idea of the proposed informal "test" is ...
- 131k
11
votes
3
answers
8k
views
How to extract information from a scatterplot matrix when you have large N, discrete data, & many variables?
I'm playing around with the breast cancer dataset and created a scatterplot of all attributes to get an idea for which ones have the most effect on predicting the class ...
- 481
73
votes
3
answers
175k
views
How to actually plot a sample tree from randomForest::getTree()? [closed]
Anyone got library or code suggestions on how to actually plot a couple of sample trees from:
getTree(rfobj, k, labelVar=TRUE)
(Yes I know you're not supposed ...
- 1,496
71
votes
3
answers
91k
views
When are Log scales appropriate?
I've read that using log scales when charting/graphing is appropriate in certain circumstances, like the y-axis in a time series chart. However, I've not been able to find a definitive explanation as ...
- 1,561
58
votes
3
answers
50k
views
How do I find peaks in a dataset?
If I have a data set that produces a graph such as the following, how would I algorithmically determine the x-values of the peaks shown (in this case three of them):
- 581
57
votes
4
answers
75k
views
Would PCA work for boolean (binary) data types?
I want to reduce the dimensionality of higher order systems and capture most of the covariance on a preferably 2 dimensional or 1 dimensional field. I understand this can be done via principal ...
- 757
32
votes
6
answers
13k
views
Problems with pie charts
There seems to be in increasing discussion about pie charts.
The main arguments against it seem to be:
Area is perceived with less power than length.
Pie charts have very low data-point-to-pixel ...
- 1,705
25
votes
3
answers
30k
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 ...
- 251
12
votes
1
answer
2k
views
Box plot notches vs. Tukey-Kramer interval
The "notch" help document (or original text) from boxplot in 'R' gives the following:
If the notches of two plots do not overlap this is ‘strong evidence’
that the two medians differ (Chambers et ...
- 9,853
9
votes
2
answers
2k
views
Does Simpson's Paradox cover all instances of reversal from a hidden variable?
The following is a question about the many visualizations offered as 'proof by picture' of the existence of Simpson's paradox, and possibly a question about terminology.
Simpson's Paradox is a fairly ...
- 2,049
69
votes
9
answers
24k
views
How to visualize what ANOVA does?
What way (ways?) is there to visually explain what is ANOVA?
Any references, link(s) (R packages?) will be welcomed.
- 21.9k
16
votes
2
answers
9k
views
Is it possible to create "parallel sets" plot using R?
Thanks to Tormod question (posted here) I came across the Parallel Sets plot. Here is an example for how it looks:
(It is a visualization of the Titanic dataset. Showing, for example, how most of ...
- 21.9k
12
votes
1
answer
29k
views
Graphing a Probability Curve for a Logit Model With Multiple Predictors
I have the following probability function:
$$\text{Prob} = \frac{1}{1 + e^{-z}}$$
where
$$z = B_0 + B_1X_1 + \dots + B_nX_n.$$
My model looks like
$$\Pr(Y=1) = \frac{1}{1 + \exp\left(-[-3.92 + 0....
- 2,645
10
votes
3
answers
1k
views
First quick glance at a dataset
Please pardon my ignorance, but...
I keep finding myself in a situation, where I'm faced with a bunch of new data I managed to find. This data usually looks something like this:
...
- 203