Population and Sample:

Population Or Statistical Population:

a population or a statistical population is a set or a collection of all Objects, and individuals or measurements or recordings,  Which may either be finite and or non finite, which has some relevance to some interest or some characteristics, the characteristic may be Heights, weights, ages, mases  number etc. the population is said to be of two types

   (i) Real Population:

real population is one whose individuals or recordings are unpredictable with out properly listing them, we need to first record them and know about the individuals

For Example:

(i)      Heights of college students

since we will not be able to know about the heights of the students unless we record them one by one

(ii)  Daily temperature

     (ii)Hypothetical population:

The population whose individuals are predictable even with out actually performing the experiment, or recording the individuals.

For Example:

(i)    A coin tossed

since can predict the possible out comes even with out listing them so this is an hypothetical population.

            Sample:

A sample is any subset or any part of a population, the number of individuals and observation in the sample are known as sample size, which is denoted by small “n”

       Parameter and Statistic:

A parameter is any quantity or a value which is calculated from the whole population,

a population mean,  a population variance are the examples of parameters

While a Statistic is any value is calculated from the sample, with out considering the whole population.

Observations and variable

In Statistics the term Observations refers to some information, which are numerically recorded Or Observations are the recorded values of every element of a characteristic,

for example:   Physical measurements(Weights and heights)

On the other hand variable as name suggests refers to a characteristic which changes it values from individual to individual, place to place and time to time.

For example:  height, weight, gender are variables and their values taken from different people are observations.

Qualitative and Quantitative variables:

Qualitative variable:

A variable which can not  be expressed in numeric form. or a variable whose values or observations can not be numerically recorded.  qualitative variable is also know as an Attribute.

For example:  Blood group, Colors of cars, gender of students etc.

Quantitative Variable:

Opposite to the qualitative variable we have a quantitative variable, Which refers to a variable which can be numerically expressed.

For example: age of the students. income of families.

       Discrete and  Continuous Variables:

Discrete variable:

discrete variable is a sub type of quantitative variable. It is a variable which can assume or take only discrete (non decimal) or a whole numbers.

For example:  number of student in a class or a college

Income of individuals

Continuous variable:

A variable which can assume any value fractional or integer in a give range or interval.

For example:

Age of the students

temperature of a place

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