Two marks Questions with Answers

Two Marks Questions with Answers

Q.1 What is correlation ?

Ans. : Correlation refers to a relationship between two or more objects. In statistics, the word correlation refers to the relationship between two variables. Correlation exists between two variables when one of them is related to the other in some way.

Q.2 Define positive and negative correlation.

Ans. :

• Positive correlation : Association between variables such that high scores on one variable tends to have high scores on the other variable. A direct relation between the variables.

•  Negative correlation: Association between variables such that high scores on one variable tends to have low scores on the other variable. An inverse relation between the variables.

Q.3 What is cause and effect relationship?

Ans. If two variables vary in such a way that movement in one are accompanied by movement in other, these variables are called cause and effect relationship.

Q.4 Explain advantages of scatter diagram.

Ans. 1. It is a simple to implement and attractive method to find out the nature of correlation.

2. It is easy to understand.

3. User will get rough idea about correlation (positive or negative correlation).

4. Not influenced by the size of extreme item.

5. First step in investing the relationship between two variables.

Q.5 What is regression problem?

Ans. For an input x, if the output is continuous, this is called a regression problem.

Q.6 What are assumptions of regression?

Ans. The regression has five key assumptions: Linear relationship, Multivariate normality, No or little multi-collinearity and No auto-correlation.

Q.7 What is regression analysis used for?

Ans. : Regression analysis is a form of predictive modelling technique which investigates the relationship between a dependent (target) and independent variable (s) (predictor). This technique is used for forecasting, time series modelling and finding the causal effect relationship between the variables.

Q.8 What are the types of regressions ?

Ans. Types of regression are linear regression, logistic regression, polynomial regression, stepwise regression, ridge regression, lasso regression and elastic-net regression.

Q.9 What do you mean by least square method?

Ans. Least squares is a statistical method used to determine a line of best fit by minimizing the sum of squares created by a mathematical function. A "square" is determined by squaring the distance between a data point and the regression line or mean value of the data set.

Q.10 What is correlation analysis?

Ans. Correlation is a statistical analysis used to measure and describe the relationship between two variables. A correlation plot will display correlations between the values of variables in the dataset. If two variables are correlated, X and Y then a regression can be done in order to predict scores on Y from the scores on X.

Q.11 What is multiple regression equations?

Ans. Multiple linear regression is an extension of linear regression, which allows a response variable, y to be modelled as a linear function of two or more predictor variables. In a multiple regression model, two or more independent variables, i.e. predictors are involved in the model. The simple linear regression model and the multiple regression model assume that the dependent variable is continuous.