How to Visualize Numerical Variables
 To Visualize Numerical Variables we use the following
 Frequency Distribution Tables
 Histograms
 Consider the following dataset with each numerical variable appearing only once
 It makes more sense to group the numerical data into intervals
 Generally statisticians prefer 5 to 20 intervals, but it depends on volume of the data
 The formula for interval width
(largest number  smallest number)/number of desired intervals
 Then according to convience we can round the interval width
 A number is included in an interval if that number
 Greater than lower bound
 is lower and equal to upper bound
 The frequency distribution table will be as shown below
 Histograms:
 These are one of the most common ways to reprsent numerical data.
 Each bar has width of the interval.
Exercise: Represent the Frequency Distribution table and histogram for the following data

Refer Here for the excel with dataset

Frequency Distribution Table:

Histogram
Two Variable Relationships
 Till now we have been dealing with single variables (Categorical and numerical variables)
 Now lets try to focus on how to visualize relationship between two variables
 For this lets start with categorical variables
 Cross Tables (Contingency tables):
 These are used to represent categorical variables.
 One set of categories is labelling the rows and other set is labelling the columns
 Side by Side Bar Chart: A common way to represent data from a cross table is by using a side by side bar chart
 Refer Here for the excel sheet
 Cross Tables (Contingency tables):
 When we want to represent relationship between two numerical variables in the same graph, we usually use a scatter plot