There are many other packages which are used by econometricians, include Eviews, Gretl, PcGive, Python, RATS, SAS.

1. Statistics is not suitable to the study of qualitative phenomenon
2. Statistical laws are not exact:
3. Statistics table may be misused:
4. Statistics is only one of the methods of studying a problem.

i. X on Y => X = a + by
ii. Y on X => Y = a + bx

It cannot establish the exact degree of correlation between the variables, but provides direction of correlation and depicts it is high or low.

(1) It is very simple and non- mathematical method
(2) it is not influenced by the size of extreme item.
(3) It is the first step in resting the relationship between two variables.

The Correlation is said to be negative when the values of variables move in the opposite directions. Ex. Y= a – bx
Ex 1: Price and demand for a commodity move in the opposite direction.

1. The correlation is said to be positive if the values of two variables move in the same direction.
2. Ex 1: If income and Expenditure of a Household may be increasing or decreasing simultaneously. If so, there is positive correlation. Ex. Y= a + bx

1. It is defined as the positive square-root of the arithmetic mean of the square of the deviations of the given observation from their arithmetic mean.
2. The standard deviation of the population is denoted by the Greek letter σ (sigma) The standard deviation of sample is denoted as 's'.

Econometrics may be defined as the social science in which the tools of economic theory, mathematics and statistical inference are applied to the analysis of economic phenomena.

(i) Regression means going back and it is a mathematical measure showing the average relationship between two variables.
(ii) It indicates the cause and effect relationship between the variables and establishes functional relationship.

(i) Correlation is a statistical device that helps to analyse the covariation of two or more variables.
(ii) Correlation is the relationship between two or more variables which vary with the other in the same or the opposite direction.

(i) Based on characteristics there are quantitative and qualitative data.
(ii) Qualitative data is classified as nominal data and rank data.
(iii) Based on the data sources there are primary data and secondary data.

The branch of statistics concerned with using sample data to make an inference about a population of data is called Inferential Statistics.

There are two major types of statistics.
(i) Descriptive statistics
(ii) Inferential statistics

(i) Statistics as a science of estimates and probabilities.
(ii) Statistics is the collection, organisation, presentation, analysis and interpretation of numerical data.