Basic How to Read a Histogram Graph

One of the major setbacks of various data visualization methods is that they become increasingly difficult to read with larger datasets. The case is quite different for histograms, which is generally used to visualize large datasets of discrete and continuous data.

Histograms provide a visual representation of quantitative information by using the height of neatly joined rectangular confined to point the frequency of points in a class interval. This graph tin exist generated manually by drawing it with a direct ruler, or digitally using Excel.

Constructing a histogram is quite easy when done digitally. Therefore, this article will comprehend details most what a histogram is and how nosotros can create them digitally using Excel.

What is a Histogram Graph?

A histogram graph is a graph that is used to visualize the frequency of detached and continuous data using rectangular bars. The rectangular bars bear witness the number of data points that autumn into a specified class interval.

Also known equally a histogram chart, the form intervals (or bins) are non always of equal size across the horizontal axis. When constructing a histogram chart, the get-go matter to practice subsequently data collection is to make up one's mind the bins or form intervals.

The information should exist grouped according to this interval, then a frequency of the data that autumn into these groups will be taken. Since the class intervals are commonly a continuous range of values, different bar charts, the rectangular pars are non spaced (i.e. they affect each other).

Features of a Histogram Graph

A histogram graph is a popular graphing tool that provides a visual representation of data distribution. In order to identify a histogram nautical chart, here are some qualities yous may need to expect out for.

Title

The title of a histogram is what gives an insight into the data visualized on the graph. Information technology summarizes the information depicted on the histogram chart.

With a title on a histogram chart, a tertiary party tin can easily depict what the graph is almost without going any further to read the graph itself. In the analogy in a higher place, the title of the histogram chart is Histogram.

Axes

A histogram chart has ii axes, the vertical and the horizontal axis. The vertical axis on the histogram chart indicates the frequency, while the horizontal centrality indicates the form intervals or bins.

These 2 axes are unremarkably labeled with what they correspond, giving more meaning to the championship of the histogram graph. The horizontal (x) axis shows the scale of values in which the class interval is measured.

Each of these axes usually has a characterization that describes the kind of information plotted on each axis. In this case, the horizontal label is Bin while the vertical label is Frequency

Bars

The bars are the body of a histogram graph, which mainly visualizes the data set. The bars on a histogram chart are rectangular in shape, and they bespeak the number of times values fall in each class interval.

The height of the confined shows the frequency, while the bar width indicates interval. Histogram graphs with uniform course intervals usually have the same width.

Scale

The scale of a histogram is a set of numbers used to measure or quantify the dataset on the graph. This is part of what determines the width and height of each rectangular bar on the histogram chart.

Information technology is what describes how each unit on the horizontal and vertical axes are structured. In the illustration, ane unit on the horizontal centrality is equivalent to 20, while 2 unit on the vertical centrality is equivalent to two.

Histographs

Histographs are graphs formed by joining the meridian midpoint of the rectangular bars on an existing histogram chart. Also known equally a frequency polygon, they are usually used when visualizing a dataset of continuous variables.

In other words, we may say that histographs are line charts drawn on a histogram chart, where the mid-apex signal of the rectangular confined is the data points.

Not all histogram charts accept a histograph. However, when added to a histogram chart, it is very useful in giving more information well-nigh the dataset.

Types of Histogram Graph

Histogram graphs are classified into different types based on the distribution of the rectangular confined on the graph. That is, the way the bars are shaped and the entire graph structure.

The various distributions of histogram charts are highlighted below:

Normal Distribution

A histogram chart is said to be of the normal distribution if it is bell-shaped. As the proper name implies, it is the normal or typical structure a histogram distribution is expected to prefer, even if it is not "normal".

In some cases, a histogram graph tin be said to be normally distributed past merely taking a wait at information technology. Yet, other distributions are similar to a normal distribution, making it necessary to perform statistical calculations before a distribution tin be said to be normal.

Bimodal Distribution

A bimodal distribution is an outcome of combining ii dissimilar processes in one dataset. This distribution contains 2 different normally distributed graphs.

For example, the data collected from the 2 divisions of a class (e.g. Course 1A and Grade 1B) has a possibility of being bimodal. Looking like the back of a double-humped camel, it is also referred to every bit double-peaked distribution.

Skewed Distribution

A skewed distribution is an asymmetric graph with an off-center elevation tending towards the limit of the graph (or away from the tail). In that location are ii types of skewed distributions, namely; right-skewed and left-skewed distributions.

In a correct-skewed distribution, the tail of the graph is on the right-mitt side. It is likewise known as a positively skewed distribution.

On the other hand, a left-skewed distribution has its tail on the left-hand side, and is also known as a negatively skewed distribution.

Random Distribution

This type of distribution lacks a particular pattern and produces several peaks. Hence, information technology is too referred to as multimodal distribution.

Random distribution is usually generated when a dataset containing variables with different properties are combined. In this case, the data should be sorted and separately analyzed.

Border Peak Distribution

The edge height distribution is very similar to the normal distribution, with the distinguishing factor being that the one-time has a big peak at one of the tails.

This kind of distribution is usually generated due to an error in the histogram graph construction.

Comb Distribution

Equally the name suggests, the bars in a comb distribution have a comb-like structure. These confined alternate in between tall and brusk, making the graph look like the rima oris of a comb.

The comb distribution is usually generated due to rounding errors in the data prepare.

Truncated Distribution

A truncated distribution is generated when the tail of a normal distribution is cut off in the resulting histogram chart. Cutting off the tail sometimes gives information technology a heart-like shape, resulting in it being called a heart-cut distribution.

Histogram Graph Examples

Example i: ABC Company is trying to reduce customer waiting fourth dimension in queues for ameliorate client satisfaction. To practice this, they took a random customer and interviewed him on the amount of fourth dimension he has had to wait in the queue in the past 10 days.

The tabular array beneath is the outcome of this interview. Create a histogram chart using this information. Hence, decide what kind of distribution the graph is

Solution: As shown below, we take created a histogram with 4 bins and iv frequencies. The horizontal axis shows the range of waiting time, while the vertical axis indicates the average number of customers that experience each interval of waiting time.

The resulting histogram chart has a randomized distribution.

Example 2: A philanthropist wants to donate supplies to a less privileged community. In order to determine the quantity and kind of supplies to donate, a survey was carried out in the community.

The goal of this survey is to find out the age census of community residents. Later on conducting this survey, it was visualized on a histogram for like shooting fish in a barrel analysis equally shown below.

Given that the Number of People indicated in the graph is in hundreds, make up one's mind the population of people in each historic period bracket, then utilise your consequence to find out which of these brackets have the highest population.

Solution: Since the number of people specified on the histogram chart is in hundreds, and then the number of people that belongs to each age bracket is:

0-20: 4*100 = 400 people

twenty-twoscore: seven*100 = 700 people

xl-60: 2*100 = 200 people

Conspicuously, the bracket with the highest population is the 20-40 age subclass. This ways that the majority of the residents if this community are between the ages of 20 and 40.

Uses of Histogram Graph

Identification of Mode in a Dataset

Without circuitous mathematical computations, i can easily identify the most mutual process issue in a dataset. Past visualizing the collected data on a histogram chart, the outcome with the highest frequency will hands stand up out as the tiptop of the graph.

Identifying information construction

1 can hands spot trends in the information when reading a histogram nautical chart. This tin exist helpful in making predictions, optimizing processes, and identifying possible issues.

Spotting deviations in data

You can hands spot deviations in data when visualizing using a histogram compared to some other data visualization methods. This is very useful in cases where you are collecting data over time.

Immediately there is a deviation in the information, the deviation is noticed on the histogram chart. This volition easily assistance you permit you inspect the information drove process and brand amends if the difference is caused past human error.

Histogram vs Bar Chart

Although possessing very similar structures and characteristics, histogram charts and bar charts take quite a number of differences. These differences are what will assist the states in recognizing these charts when we come across them.

Therefore, this section will dive into the similarities and differences betwixt bar charts and histograms.

Differences

Characteristics

The rectangular bars in a bar nautical chart are spaced while the rectangular confined in a histogram are joined together. Also, the horizontal labels on the bar graph are usually discrete or nominal information.

Histograms, on the other hand, accept their axes labeled with the bins or course intervals of the data set.

Uses

In data analysis, bar graphs are used to measure the frequency of categorical data, while histograms measure ordinal and quantitative (interval and ratio) information. Although the vertical centrality of both graphs is detached, the horizontal centrality of a bar graph is categorical while that of a histogram is numerical.

Ordering

The rectangular bars on a bar graph are usually arranged in order of decreasing height. Histograms, on the other hand, have their rectangular bars ordered according to where they autumn in the class interval.

Although the course intervals are bundled in ascending order, this does not mean the rectangular confined will necessarily be bundled the same way. This is because of the frequency of each interval, which randomly varies depending on the dataset.

Similarities

Characteristics

Both histograms and bar charts accept a championship, axes, scale, and rectangular bars. By merely looking at both graphs, they await a lot similar each other. This is mainly considering they both employ the use of rectangular bars to visualize information.

Uses

Bar charts and histograms are both used to make up one's mind the mode or frequency of the elements in a dataset. The height of the rectangular bars corresponds to the frequency of a particular chemical element in the dataset.

The simple way of reading these 2 graphs is by following the elementary unofficial rule which states that, "The college the bar, the college the frequency, and vice versa."

Histogram Graph in Excel

To construct a histogram chart using Excel, follow these few simple steps:

Stride ane: Enter your data into the Excel workbook as shown in the figure below.

The inputs are the set of random variables we desire to visualize using Excel, Bin Range is the range of values yous desire to be indicated on the horizontal axis. This is what determines the width of the rectangular bars and the scale of the horizontal axis.

Step two: Go to Data>Analysis|Information Assay. If yous can't observe the Data Analysis tab, it means that yous haven't installed the Analysis Toolpak plugin. To install the plugin, go to File>Options and a dialogue box similar to the one below volition pop upward.

Click on Analysis Toolpak, then on the Go button. Another dialogue box similar to the diagram below will popup.

Check Analysis Toolpak and click OK as shown above. Your Data Assay tab volition now bear witness up in your Analysis menu.

Step 3: After clicking on Data Analysis, a dialog box similar to the ane beneath will pop up.

Click on Histogram and then OK to get to the side by side step.

Step 4: Enter the input range and bin range, then check the necessary options every bit shown in the diagram below. Click OK and you will have your histogram nautical chart.

Step 5: In the diagram below, our generated histogram chart looks more than similar a bar chart with space in between the bars.

Edit the gap in between the rectangular confined past highlighting all the bars, and then become to Format Data Series>Series Options. Eliminate the dap by reducing Gap Width to 0% equally shown beneath.

Separate the confined from each other by calculation a Border Color to the bars.

Step 6: Edit the bins or class intervals by right-clicking on the graph, then going to Select Data Series. This will bring a prompt similar to the one beneath.

Click Edit in the Horizontal (Category) Axis Labels to edit the bin labeling.

Click OK and in that location you have your histogram nautical chart.

By merely looking at the symmetry of this graph, we tin can conclude that it is of random distribution.

Disadvantages of a Histogram Graph

It tin can only exist used to visualize continuous information. Since the graphs are ordinarily joined together, it will be wrong to employ a histogram to visualize discrete information. This tin can only be washed using a bar chart.
Since data is grouped into different categories, histograms cannot read exact values. You cannot identify specific data points in the graph by merely reading the histogram chart.
It cannot be used to compare ii information sets.

Determination

A histogram chart is a bang-up visualization tool for studying the variation of big data sets. It is one of the most used data visualization methods in statistical analysis.

Histograms are ane of the seven basic tools of quality control considering of their simplicity and power to solve the majority of quality-related issues. Quality control analysts study different things in the histogram chart, including the distribution, width, and height of the rectangular bars.

Although it is commonly said that the height of a histogram indicates the frequency of occurrences in the bin, this does not utilise to all cases. In cases whereby the histogram does non have equal bins, the frequency of the interval is adamant by the expanse of the rectangular bars.

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