Question

show an example of correlation analysis

Answer 1

Correlation analysis is carried out to investigate whether any kind of association exists between two variables (such as, height and weight).
As an example, we carry out a small observational study involving 20 school students to check whether any association exists between total marks obtained out of 100 (y) (dependent variable) and number of hours studied per day (x) (independent variable). The data is given below.

Student No.	x	y
1	7	69
2	9	72
3	9	73
4	7	83
5	10	65
6	8	64
7	6	74
8	5	51
9	10	74
10	4	79
11	9	81
12	9	52
13	7	55
14	8	60
15	9	84
16	3	80
17	3	83
18	5	82
19	3	75
20	9	90

We input this data table in MS Excel and use the CORREL function to compute the sample correlation coefficient. The value comes out to be -0.1629. This means that there exists a weak, negative linear association between the two variables.