Dear Jinish,
In statistics, Spearmans rank correlation coefficient or Spearmans rho, named after Charles Spearman and often denoted by the Greek letter
(rho) or as
, is a non-parametric measure of statistical dependence between two variables. It assesses how well the relationship between two variables can be described using a monotonic function. If there are no repeated data values, a perfect Spearman correlation of +1 or −1 occurs when each of the variables is a perfect monotone function of the other.
Example
In this example, we will use the raw data in the table below to calculate the correlation between the IQ of a person with the number of hours spent in front of TV per week.
IQ,  |
Hours of TV per week,  |
| 106 |
7 |
| 86 |
0 |
| 100 |
27 |
| 101 |
50 |
| 99 |
28 |
| 103 |
29 |
| 97 |
20 |
| 113 |
12 |
| 112 |
6 |
| 110 |
17 |
First, we must find the value of the term
. To do so we use the following steps, reflected in the table below.
- Sort the data by the first column (
). Create a new column
and assign it the ranked values 1,2,3,...n.
- Next, sort the data by the second column (
). Create a fourth column
and similarly assign it the ranked values 1,2,3,...n.
- Create a fifth column
to hold the differences between the two rank columns (
and
).
- Create one final column
to hold the value of column
squared.
IQ,  |
Hours of TV per week,  |
rank  |
rank  |
 |
 |
| 86 |
0 |
1 |
1 |
0 |
0 |
| 97 |
20 |
2 |
6 |
−4 |
16 |
| 99 |
28 |
3 |
8 |
−5 |
25 |
| 100 |
27 |
4 |
7 |
−3 |
9 |
| 101 |
50 |
5 |
10 |
−5 |
25 |
| 103 |
29 |
6 |
9 |
−3 |
9 |
| 106 |
7 |
7 |
3 |
4 |
16 |
| 110 |
17 |
8 |
5 |
3 |
9 |
| 112 |
6 |
9 |
2 |
7 |
49 |
| 113 |
12 |
10 |
4 |
6 |
36 |
With
found, we can add them to find
. The value of n is 10. So these values can now be substituted back into the equation,

which evaluates to ρ = −0.175757575... with a P-value = 0.6864058 (using the t distribution)
This low value shows that the correlation between IQ and hours spent watching TV is very low
Best Of luck
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