What is correlation and linear regression Please give real l

What is correlation and linear regression? Please give real life examples

Solution

correlation:
we estimate a sample correlation, ranges between -1 and +1 and quantifies the direction and strength of the linear association between the two variables.          
the sign of the correlation coefficient indicates the direction of the association. The magnitude of the correlation coefficient indicates the strength of the association.

For example, a correlation of r = 0.9 suggests a strong, positive association between two variables, whereas a correlation of r = -0.2 suggest a weak, negative association. A correlation close to zero suggests no linear association between two continuous variable

eg:
A small study is conducted involving infants to investigate the association between gestational age at birth, measured in weeks, and birth weight, measured in grams.

Regression
useful for assess and adjusting for confounding

Eg:
assess the association between total cholesterol and body mass index (BMI) in which total cholesterol is the dependent variable, and BMI is the independent variable. In regression analysis, the dependent variable is denoted Y and the independent variable is denoted X. So, in this case, Y=total cholesterol and X=BMI.