How do you calculate Spearman's rank correlation?

Answer 1

# State the null hypothesis i.e. "There is no relationship between the two sets of data." # Rank both sets of data from the highest to the lowest. Make sure to check for tied ranks. # Subtract the two sets of ranks to get the difference d. # Square the values of d. # Add the squared values of d to get Sigma d2. # Use the formula Rs = 1-(6Sigma d2/n3-n) where n is the number of ranks you have. # If the Rs value...

... is -1, there is a perfect negative correlation.

...falls between -1 and -0.5, there is a strong negative correlation.

...falls between -0.5 and 0, there is a weak negative correlation.

... is 0, there is no correlation

...falls between 0 and 0.5, there is a weak positive correlation.

...falls between 0.5 and 1, there is a strong positive correlation

...is 1, there is a perfect positive correlation

between the 2 sets of data. # If the Rs value is 0, state that null hypothesis is accepted. Otherwise, say it is rejected. (sourced from http://www.revision-notes.co.uk/revision/181.html)