PMCC vs Standard Deviation
Could someone help/explain this to me. The mark scheme didn't really help at all.
A student had 2 sets of bivariate data. He found the standard deviation and pmcc of each set.
Set A: pmcc = 0.9....sd = 1
Set B: pmcc = 1.......sd = 0.9
Why can the results for set A be correct but not both results for set B?
A student had 2 sets of bivariate data. He found the standard deviation and pmcc of each set.
Set A: pmcc = 0.9....sd = 1
Set B: pmcc = 1.......sd = 0.9
Why can the results for set A be correct but not both results for set B?
Original post by Fuenciado
Could someone help/explain this to me. The mark scheme didn't really help at all.
A student had 2 sets of bivariate data. He found the standard deviation and pmcc of each set.
Set A: pmcc = 0.9....sd = 1
Set B: pmcc = 1.......sd = 0.9
Why can the results for set A be correct but not both results for set B?
A student had 2 sets of bivariate data. He found the standard deviation and pmcc of each set.
Set A: pmcc = 0.9....sd = 1
Set B: pmcc = 1.......sd = 0.9
Why can the results for set A be correct but not both results for set B?
What's "sd" here? Standard deviation of what?
Original post by Fuenciado
Could someone help/explain this to me. The mark scheme didn't really help at all.
A student had 2 sets of bivariate data. He found the standard deviation and pmcc of each set.
Set A: pmcc = 0.9....sd = 1
Set B: pmcc = 1.......sd = 0.9
Why can the results for set A be correct but not both results for set B?
A student had 2 sets of bivariate data. He found the standard deviation and pmcc of each set.
Set A: pmcc = 0.9....sd = 1
Set B: pmcc = 1.......sd = 0.9
Why can the results for set A be correct but not both results for set B?
Do you have a link to the original question and to the mark scheme?
Original post by davros
Do you have a link to the original question and to the mark scheme?
Wasn't working as an image so I've done it as an attachment
Original post by Fuenciado
Wasn't working as an image so I've done it as an attachment
R sub s is spearman's rank, not standard deviation. Lower case sigma is standard deviation.
Original post by Protoxylic
R sub s is spearman's rank, not standard deviation. Lower case sigma is standard deviation.
Yeah I know, I didn't even notice that I'd called it the wrong thing.
I've done like 26 hours of stats in the last 3 days , I think my brain is broken.
Original post by DFranklin
So, now you know it's Spearman's Rank, do you know how to procede?
Not really
Original post by Fuenciado
Not really
Pmcc is a measure of how good a fit a linear realationship is, with "1" (or "-1") being a perfect fit.
Spearmans is a measure of how good a fit a monotonic relationship is, with "1! (or "-1") being a perfect fit.
With that in mind, which of the two sets are giving you problems?
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