topic: Frequency distribution

A frequency distribution is a summary of data that shows the number of observations (frequency) in each category or interval. It functions as a method to systematically arrange and present unprocessed data in a meaningful way, facilitating analysis and the derivation of conclusions. Widely applied in statistics, frequency distributions provide a descriptive overview of the spread of values within a dataset.

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Key components

Here’s are key components of frequency distribution:

Categories or intervals: These are the groups or ranges into which the data is divided. For example, in a dataset of weight based on age, categories could be weight ranges like 0-10, 11-20, 20-30 and so on. Frequency : The frequency of a category denotes the count of observations or data points situated within that specific category, indicating the frequency with which a particular value or range appears in the dataset.

Cumulative Frequency: Cumulative frequency is the running total of frequencies as you move through the categories. It helps in understanding the total number of observations up to a certain point in the distribution.

Relative Frequency: Relative frequency is the proportion of observations in a category relative to the total number of observations. It is calculated by dividing the frequency of a category by the total number of observations.

Here’s a simple example to illustrate the concept:

Suppose you have a dataset of exam scores for a class of students:

To create a frequency distribution, you would organize the data and count the occurrences of each score:

Score Range(categories or intervals) Frequency Cumulative Frequency Relative Frequency
0-10 6 6 6/4=1.5
10-20 2 6+2=8 2/4=0.5
20-30 2 8+2=10 2/4=0.5
30-40 4 10+4=14 4/4=1
  • There are four categories representing different score ranges.
  • The frequency column indicates how many students scored within each range.
  • A cumulative frequency column could be added to show the running total.
  • Relative frequencies could be calculated by dividing each frequency by the total number of students.

Check your understanding

Looking at the table above, can you understand what each of the columns means?


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