# The value of spearman's rank correlation coefficent no of observations was found to be 2/3. The sum of the squares of differences between the corresponding ranks was 55. Find the no. of pairs.

As we know

${r}_{k}=1-\frac{6\underset{}{\sum {D}^{2}}}{{N}^{3}-N}$

Where

r

_{k = }Coefficient of rank correlation

D = Rank differences

N = Number of pairs

Given -

r

_{k = 2/3}

ΣD

^{2}= 55

N = ?

Regards

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