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Frequency Distribution and Data Presentation

A frequency distribution is a table that displays the frequency of various outcomes in a sample. Each entry in the table contains the frequency or count of the occurrences of values within a particular group or interval, and in this way, the table summarizes the distribution of values in the sample.
Organizing Data.
  • 1.Arrange data into an array
  • 2. Decide on the number of classes( k)
    3. Calculate the class interval
    4. Prepare a tally sheet
There are two types of Frequency: 
  • Categorical frequency distribution.
  • Grouped frequency distribution.
Categorical Frequency Distributions
The categorical frequency distribution is used for data that can be placed in specific categories or represent values of a qualitative variable.
Grouped Frequency Distributions:
When the data are numerical and their range is large, the data must be grouped into classes that are more than one unit in length.
Histogram
The histogram is an accurate graphical representation of the distribution of numerical data.



Frequency Polygon
Frequency polygons are a graphical device for understanding the shapes of distributions. They serve the same purpose as histograms but are especially helpful for comparing sets of data. Frequency polygons are also a good choice for displaying cumulative frequency distributions.


Pie Chart

Pie chart is used to present Nominal or Ordinal data. Each slice represents a category. The size of each category is proportional to the percentage of that category to the overall sample size.

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