Data Sets

A Data set is a set or collection of data. This set is normally presented in tabular pattern. Every column describes a particular variable. And each row corresponds to a given member of the data set, as per the given question. It describes values for each variable for unknown quantities such as height, weight, temperature, volume, etc of an object or values of random numbers. The values in this set are known as a datum. The data set consists of data of one or more members corresponding to each row.

Definition and Types of Data Sets

A data set is an ordered collection of data. It can be a bunch of tables, schema and other objects. The data are essentially organized to a certain model that helps to process the needed information. The set of data is any permanently saved collection of information which usually contains either case-level, gathered data, or statistical guidance level data.

We have different types of data sets available for different types of information, in statistics.

Numerical Data Sets

A set of all numerical data. It deals only with numbers. Some of the examples are;

  • Weight and height of a person
  • The count of RBC in a medical report
  • Number of pages present in a book

Bivariate Data Sets

A data set which has two variables is called a Bivariate data set. It deals with the relationship between the two variables.

Example: To find the percentage score and age of the students in a class. Score and age can be considered as two variables

Multivariate Data Sets

A data set with multiple variables.

Example: If we have to measure the length, width, height, volume of a rectangular box, we have to use multiple variables to distinguish between those entities.

Categorical Data Sets

Categorical data sets represent features or characteristics of a person or an object.

Example:

  • A person’s gender (male or female)
  • Marital status (married/unmarried)

Correlation Data Sets

The set of values which demonstrate some relationship with each other indicates correlation data sets. Here the values are found to be dependent on each other.

Example: A tall person is considered to be heavier than a short person. So here the weight and height variables are dependent on each other.

Mean, Median, Mode and Range of Data-Sets

Mean of a data-set is the average of all the observations present in the table. It is the ratio of the total number of observations to the total number of elements present in the data-set. The formula of mean is given by;

Mean of a data set

Median of a data-set is the middle value of the collection of data when arranged in ascending order and descending order.

Mode of a data-set is the variable or number or value which is repeated two or more times in the set.

Range of a data set is the difference between the maximum value and minimum value.

Range = Maximum Value – Minimum Value

Example

Find the mean, mode, median and range of the given data set.

{2, 4, 6, 8, 2, 10, 12}

Solution: Given, {2, 4, 6, 8, 2, 10, 12} is a set of data.

Mean = 2+4+6+8+2+10+12/7 = 44/7

To find median we have to first arrange the given data in ascending or descending order

So, {2,2,4,6,8,10,12}. Thus,

Median = 6

Mode = 2

Range = 12-2 = 10

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