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In this video we will learn about frequency distributions and once we know about frequency distribution

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we will learn how to draw a histogram

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to when we are trying to draw frequency distribution.

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We are basically trying to summarize the data so that we have different categories from that data and

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we assign the number of occurrences of each category in that data.

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For example if I have data of students of for college and against their name I have the branch that

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they belong to.

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I can create a table like this in which I have summarized that how many of those students belong to

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each branch.

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So in an engineering college in that list hundred students belong to computer science branch 82 and

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belong to mechanical engineering branch and so on.

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When we have the categories like this that is the categories are discrete we have five different branches

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and to each branch we can clearly assign these student.

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This is called qualitative data or categorical data.

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And this type of distribution is called up frequency distribution for qualitative reader.

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So that raw data would be stored in name in front of that is read in the branch to which that's true

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and belongs and we have this list for 420 students and we summarize that data as how many students belong

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to each group.

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Once we have a say in these frequencies we can also find out the relative frequency of each category

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by using this formula that is frequency of that category divided by some of all frequencies.

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That is if I want to find out the relative frequency of students blank belonging to biotechnology it

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is 60 that is the frequency of this category divided by the total frequency which is 420 is equal to

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nearly fourteen point two percent.

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So when we build a frequency distribution for qualitative data that is there are clear discrete categories

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and we draw a graph of it.

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It is similar to a bar chart a graphical representation of frequency distribution for qualitative data

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is known as budget budget.

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We have already discussed we know how to draw a budget.

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If we have a data like this you can just select data die in Excel and go to budget and draw this kind

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of graph.

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The next table frequency distribution is frequency distribution for quantitative data that is continuous

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data.

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So for example if I have name of student and in front of them I have the marks of these students in

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science.

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So MOX is a continuous value from zero to hundred.

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If I want to straightaway create categories maybe I'll get a hundred categories one category of zero

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one category of two.

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One category of value 3 and that does not really make a sense.

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So when we have a continuous data we try to create ranges small ranges and within each range we assign

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the frequency of number of instances belonging to that category.

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So for example instead of creating 0 1 2 3 as categories we have greater detail 235 as one category

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35 to 55 as a matter to divide 278 added.

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And so on and within each range I have found out how many student belong to that range and assign that

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number hit to this table is frequency distribution for that continues data.

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And when we create a graph of this data that is called a histogram.

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So a graph of frequency distribution of categorical variable is called bar chart a graph of frequency

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distribution of continuous data is called a histogram.

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So how to draw a histogram when you have continuous data.

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I have outlined that process in these six steps.

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When you have a list of continuous data the first thing you need to decide is the number of classes

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that you want.

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That is the number of categories.

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For example in the previous example we have five classes to first thing you need to decide is how many

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classes you want in your table.

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Second using that number of classes we find out the class quit using this formula.

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The maximum value of data and the minimum value data what is the difference between these two values

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divided by the number of classes that we decided in first.

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Once we have class weight we can start creating the classes.

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We start by the minimum value we add classwork and we get the first class.

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This will get clear when we go through the example.

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This is the continuous data that I have.

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It is a set of 24 numbers and I want to segregate into five equal classes.

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So I have selected the number of classes with just five.

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Now I want to find out the class which I do classwork this phone by subtracting minimum value from the

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maximum value.

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Minimum value for this set of numbers is six and the maximum value is 36 to 36 minus six divided by

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number of classes which is five.

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So it comes out to six now to create the classes.

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I will start with the minimum value which is six and I will add the class word to get this upper range.

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So it is six to twelve.

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Next class will start from this value will and we will add the class word to get it.

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And so on.

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So from six to twelve will do 18 18 to 24 25 30 32 36 to avoid confusion that if we have a number 30

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to which class it will belong we usually follow this convention that party will not belong to this class.

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It would belong to this 24 to 30 class that is today will be part of the upper range and not of the

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lower range.

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Once we have created these classes we have to start assigning each number to these classes.

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So I will go to the numbers one by one and I will start adding a mark to each of these classes to whichever

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class that number belongs to.

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For example I start with 10 and belongs to this class so I add a market.

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Then there is 14 14 belong to this class.

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I add a mark here.

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I go through all these numbers and I continue adding marks in the end.

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I have this column containing Ali which is giving me how many numbers belong to each category.

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Lastly I just need to add these marks to any frequency.

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So this is how this table is created.

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And once this table is created we can create a histogram.

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So let us go to excel now and create this is to them.

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So here is the list of numbers that I had in my presentation and this is the histogram which is created

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for these numbers.

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The good thing about Excel is that you do not need to create that table to create this histogram Excel

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can create this histogram straight away.

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Using these numbers you can see from six to twelve we have two from two to 18.

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We have four.

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So basically these classes are on the horizontal axis and the height of the bar is giving you the frequency

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in each class.

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One small but important thing to note here is that Excel is using this gold and square brackets to indicate

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that which number is included and which is not for example in this 24 to 30 24 number will not be included

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in this graph.

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Therefore it has a gold bracket but 30 will be included in this bar.

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Therefore it is a square bracket so you can see for these four categories the first number is not included

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but the second is included.

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But for this first category only the first and chicken both are included.

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This is our histogram we look like.

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Let us learn how to create this histogram and delete this first so to create Instagram select the numbers

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that we have go to insert in these statistical graphs.

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This first option isn't Instagram you can see by default it has created 3D glasses with the range six

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to sixteen 16 to 26 and 26 to 36.

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Now I wanted five glasses so for that I will do the format access to open for my taxes.

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You know how to open this formatting options either right click and select the format option or you

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double click on that chart element to open formatting options for that particular element.

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So I double clicked on the horizontal axis to open it formatting options in these.

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The third option will have the specific exit options for histogram.

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Here you can change the bean rate and number of bins by default automatically created to ribbons.

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Now I want to create five bins now either I give a bin rate of value 6 which I found out.

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So this is the Instagram that I wanted to see on.

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I could have given the number of bent as for you two both will look.

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Also remember whenever you draw a histogram it is advisable that you have data labels on top of it.

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It will make it easier to find out what is the frequency of each category.

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The second type of statistical chart is up but he does chart so this is it.

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But he does chart

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it is similar to the histogram.

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The major differences the categories are sharp weight.

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These are sharper in the sense that the category which is contributing the most comes first.

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So this category had a frequency of 9 to it this coming first next county category which just contributing

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the next maximum to the total.

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So the categories are arranged in the descending order of that frequency values.

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And this line is showing the cumulative relative frequency values.

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For example the relative frequency of this category is around 35 percent.

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Then I add this second category it becomes nearly 70 percent of the third category.

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It becomes nearly 88 percent after adding fourth category.

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It becomes nearly 95 percent.

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And the last category act it two hundred percent.

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So using burrito you can estimate how many of these categories contribute to how much percentage of

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the total.

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So for example if you would like to find all those important two or three categories which are counted

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we contribute 80 percent of the total.

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And you can do that using up burrito do analysis.

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So this is how we create frequency distribution and histogram.

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Good thing about using Excel is you do not need to create a frequency distribution table to create histogram

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I told you how to do that.

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So that you understand the concept being a histogram.

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That's all for this value.