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Questions tagged [histogram]

In statistics, a histogram is a graphical representation, showing a visual impression of the distribution of data.

In statistics, a histogram is a graphical representation, showing a visual impression of the distribution of data. It is an estimate of the probability distribution of a continuous variable and was first introduced by Karl Pearson. A histogram consists of tabular frequencies, shown as adjacent rectangles, erected over discrete intervals (bins), with an area equal to the of the observations in the interval. The height of a rectangle is also equal to the frequency density of the interval, i.e., the frequency divided by the width of the interval. The total area of the histogram is equal to the number of data. A histogram may also be normalized displaying relative frequencies. It then shows the proportion of cases that fall into each of several categories, with the total area equaling 1. The categories are usually specified as consecutive, non-overlapping intervals of a variable. The categories (intervals) must be adjacent, and often are chosen to be of the same size.

Histograms are used to plot density of data, and often for density estimation: estimating the probability density function of the underlying variable. The total area of a histogram used for probability density is always normalized to 1. If the length of the intervals on the x-axis are all 1, then a histogram is identical to a relative frequency plot.

In scientific software for statistical computing and graphics, The function hist generates a histogram. It can also optionally scale it so that its total area is 1. This puts it in the right scale if one want to overlay a probability density curve.

More about it here : histogram wiki

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Is there a way to show overlapping histograms in R without adjusting transparency?

The objective is to show overlapping histograms, but I want to avoid using the alpha adjustment so that the colours remain bright. Is there a way to do this without adjusting the alpha arg? Goal is to display the colors shown…
Minnow
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How to get Histogram of all columns in a large CSV / RDD[Array[double]] using Apache Spark Scala?

I am trying to calculate Histogram of all columns from a CSV file using Spark Scala. I found that DoubleRDDFunctions supporting Histogram. So I coded like following for getting histogram of all columns. Get column count Create RDD[double] of each…
Devan M S
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Histogram matching - image processing - c/c++

I have two histograms. int Hist1[10] = {1,4,3,5,2,5,4,6,3,2}; int Hist1[10] = {1,4,3,15,12,15,4,6,3,2}; Hist1's distribution is of type multi-modal; Hist2's distribution is of type uni-modal with single prominent peak. My questions are Is there…
Raj
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Pandas: plotting two histograms on the same plot

I would like to have 2 histograms to appear on the same plot (with different colors, and possibly differente alphas). I tried import random x = pd.DataFrame([random.gauss(3,1) for _ in range(400)]) y = pd.DataFrame([random.gauss(4,2) for _ in…
meto
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Turn hist2d output into contours in matplotlib

I have generated some data in Python using matplotlib.hist2d. An example of the data is seen below. As you can see this data has some contours in it found by tracing the same color throughout the plot. I see a gamma distribution centered around…
Jon
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pandas histogram in python. possible to make probability/density instead of count?

Histogram in pandas plots the count of each bin, rather than the normalized fraction. In R, this is an option in the histogram. Is it possible in Pandas? If not, any recommendations for an easy workaround?
wolfsatthedoor
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How to create multiple histograms on separate graphs with matplotlib?

I have 5 data sets from which I want to create 5 separate histograms. At the moment they are all going on one graph. How can I change this so that it produces two separate graphs? For simplicity, in my example below I am showing just two…
Freya Lumb
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Pandas Histogram of Filtered Dataframe

This has been driving me mad for the one last hour. I can draw a histogram when I use: hist(df.GVW, bins=50, range=(0,200)) I use the following when I need to filter the dataframe for a given condition in one of the columns, for…
marillion
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How do I highlight an observation's bin in a histogram in R

I want to create a histogram from a number of observations (i.e. d <- c(1,2.1,3.4,4.5) ) and then highlight the bin that a particular observation falls in, such that I have an output that looks like this: how do I do this in R?
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local histogram equalization

I am trying to use do some image analysis in python (I have to use python). I need to do both a global and local histogram equalization. The global version works well however the local version, using a 7x7 footprint, gives a very poor result. This…
user3011255
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CSV file to Histogram in R

I'm a total newbie with R, and I'm trying to create a histogram (with value and frequency as the axises) from a csv file (just one row of values). Any idea how I can do this?
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Plot Histogram with Points Instead of Bars

Here is a question for R-users. I am interested in drawing a histogram with points stacked up, instead of a bar. For example if the data is (1,1,2,1,2,3,3,3,4,4), then I would like to see three points stacked up at 1, 2 points stacked up at 2 and so…
Ramnath
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Opacity misleading when plotting two histograms at the same time with matplotlib

Let's say I have two histograms and I set the opacity using the parameter of hist: 'alpha=0.5' I have plotted two histograms yet I get three colors! I understand this makes sense from an opacity point of view. But! It makes is very confusing to show…
mike
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numpy histogram with 3 variables

Please forgive me if this is a repeated question, I've done my best to look for a solution. This seems very straightforward but I can't seem to find anything applicable. I'm trying to generate a plot (like a heatmap) using data from 3 1-D numpy…
Teachey
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Can I trick numpy.histogram into behaving like numpy.bincount?

So, I have lists of words and I need to know how often each word appears on each list. Using ".count(word)" works, but it's too slow (each list has thousands of words and I have thousands of lists). I've been trying to speed things up with numpy. I…
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