Rank correlation, Applied Statistics

Assignment Help:

Rank Correlation

Sometimes the characteristics whose possible correlation is being investigated, cannot be measured but individuals can only be ranked on the basis of the characteristics to be measured. We then have two sets of ranks available for working out the correlation coefficient. Sometimes the data on one variable may be in the form of ranks while the data on the other variable are in the form of measurements which can be converted into ranks.

Thus, when both the underlying variables are ordinal or when the data are available in the ordinal form irrespective of the type of variable, we use the rank correlation coefficient to find out the extent of relationship between the two variables.

This rank correlation coefficient is also known as Spearman's rank correlation coefficient. Rank correlation is a non-parametric technique for measuring strength of relationship between paired observations of two variables when the data are in a ranked form.

Rank Correlation measures the degree of agreement between the two sets of ranks.

Rank Correlation Coefficient R is

  1153_rank correlation.png

where,   n   =      Number of individuals ranked

             Di   =       Difference in the ranks of the ith individual

             i     =       1, 2, ........ n

 

             Di   =       Difference in the ranks of the ith individual

             i     =       1, 2, ........ n

Example

The ranks of 8 students are given according to their marks in English and History.

Student No.

1

2

3

4

5

6

7

8

English

2

8

1

7

6

4

5

3

History

7

3

2

6

5

8

4

1                                          

 

We want to know whether or not students who are good in English are also good in History. For this the calculations are:

1531_rank correlation1.png

 

Here

1509_rank correlation2.png

= 74 and n = 8

 

R

  706_rank correlation3.png
  = 0.119  

The correlation between the ranks is seen to be low.


Related Discussions:- Rank correlation

Analysis of variance (anova), Analysis of variance allows us to test whethe...

Analysis of variance allows us to test whether the differences among more than two sample means are significant or not. This technique overcomes the drawback of the method used in

Harmonic mean, Harmonic Mean  The harmonic mean  also called harmonic  ...

Harmonic Mean  The harmonic mean  also called harmonic  average, in the total numbers of items of variable divided by the sum of r reciprocals of the values of the variable. In

the npv of the book , Bill Clinton reportedly was paid $10 million to writ...

Bill Clinton reportedly was paid $10 million to write his book My Way. The book took three years to write. In the time he spent writing, Clinton could have been paid to make speech

Cluster analysis, Cluster Analysis could be also represented more formally ...

Cluster Analysis could be also represented more formally as optimization procedure, which tries to minimize the Residual Sum of Squares objective function: where μ(ωk) - is a centr

Iterative convergence of the method, You are given the differential equatio...

You are given the differential equation dy/dx = y' = f(x, y) with initial condition y(0 ) 1 = . The following numerical method is also given: where  f n = f( x n , y n )

Inferential Statistics.., A researcher computed the F ratio for a four-grou...

A researcher computed the F ratio for a four-group experiment. The computed F is 4.86. The degrees of freedom are 3 for the numerator and 16 for the denominator. 1. Is the computed

Displacement of a simply supported beam, The displacement of a simply suppo...

The displacement of a simply supported beam subject to a uniform load is given by the solution of the following differential equation (for small displacements); and q is th

mathematical anxiety, A study was designed to investigate the effects of t...

A study was designed to investigate the effects of two variables - (1) a student's level of mathematical anxiety and (2) teaching method - on a student's achievement in a mathemati

Questionnaire, Framing of Questionnaire: Questionnaire is a schedule of...

Framing of Questionnaire: Questionnaire is a schedule of questions which is sent to the respondents for filling in by them in their own handwriting together the information rel

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd