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is spearman rank correlation coefficient = product moment correlation coefficient

It says in the mark scheme
Definition of rs is PMCC for ranks
rs being spearman's rank
the PMCC is referred to as Pearson's coefficient of correlation.
Nope, not the same
Only the same when data is already ranked
Reply 4
Original post by glad-he-ate-her
Only the same when data is already ranked


Could you please expand?
Original post by BULL14
Could you please expand?




Pearson product moment correlation


The Pearson correlation evaluates the linear relationship between two continuous variables. A relationship is linear when a change in one variable is associated with a proportional change in the other variable.For example, you might use a Pearson correlation to evaluate whether increases in temperature at your production facility are associated with decreasing thickness of your chocolate coating.


Spearman rank-order correlation


The Spearman correlation evaluates the monotonic relationship between two continuous or ordinal variables. In a monotonic relationship, the variables tend to change together, but not necessarily at a constant rate. The Spearman correlation coefficient is based on the ranked values for each variable rather than the raw data.Spearman correlation is often used to evaluate relationships involving ordinal variables. For example, you might use a Spearman correlation to evaluate whether the order in which employees complete a test exercise is related to the number of months they have been employed.
Reply 6
Original post by glad-he-ate-her
Pearson product moment correlation


The Pearson correlation evaluates the linear relationship between two continuous variables. A relationship is linear when a change in one variable is associated with a proportional change in the other variable.For example, you might use a Pearson correlation to evaluate whether increases in temperature at your production facility are associated with decreasing thickness of your chocolate coating.


Spearman rank-order correlation


The Spearman correlation evaluates the monotonic relationship between two continuous or ordinal variables. In a monotonic relationship, the variables tend to change together, but not necessarily at a constant rate. The Spearman correlation coefficient is based on the ranked values for each variable rather than the raw data.Spearman correlation is often used to evaluate relationships involving ordinal variables. For example, you might use a Spearman correlation to evaluate whether the order in which employees complete a test exercise is related to the number of months they have been employed.


Thankyou,
But why is it only the same when the data is ranked?
Original post by BULL14
Thankyou,
But why is it only the same when the data is ranked?


to calculate spearman`s we need to rank the data and then use the formula, if already ranked they will be the same, in fact PMCC is more accurate i think

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