Finland 10 marks 1993, 1996

The catalog for the article 10 marks

https://en.numista.com/catalogue/pieces3279.html

in mintage section gives:
1993 M 30 002 000 81% (fr) 9 grande queue
1996 M 3 300 000 14% (fr) 9 petite queue

Note. Obviously the percentage is from wrongly described occurrence of lines and has nothing to do with frequency as it expected to be. This is not the case of this topic and in this post onwards it is recommended not to pay attention to this nonsense.

The images of the 1993 are presented here: https://www.delcampe.net/en_GB/collectables/coins-banknotes/coins/finland/bimetallic-1993-2001-finland-10-marks-1993m-low-start-no-reserve-1337048518.html

The images of the 1996 are the main images of the article itself.

In which way is it possible to spot these 9 large at 1993 and 9 small at 1996 coins?

I didn't measure them, but the style is quite different. For the 1993 the bottom stroke of the 9 points to the left while the 1996 curves up.

Yes, the 1993 "long tail" 9 has a lot more space betwen the "head" and "tail" of the 9, as seen here:



... as for the percentages: Frequencies show the percentage of Numista users who own each year or variety among all the users who own this coin. Since some users own several versions, the sum may be greater than 100%.

I would not describe something as nonsensical when there is a logical explanation available.

So the 9 means digit in date, and not some 9 items.

It solves the riddle and make attribution possible.

The frequency is a scientific term, out of its definition , the total is always 1, no excuse can change the meaning, thus the existence of nonsense is proved. Solution: either use another word or normalize the numbers, so they will become frequencies: the sum will be 100% and no apologies for writing nonsense, smartly cited already, will be necessary.

Frequency is just the rate at which something occurs. Rate always has a numerator and a denominator, and those are clearly provided in the definiton. So, there is no problem with the use of the term frequency.

You are correct that percentage assumes a normalization relative to a denominator of 100. So if the frequencies had not have been converted to percentages, discussions like this one would have been avoided.

Quote: "tdziemia"​Frequency is just the rate at which something occurs. Rate always has a numerator and a denominator, and those are clearly provided in the definiton. So, there is no problem with the use of the term frequency.
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​You are correct that percentage assumes a normalization relative to a denominator of 100. So if the frequencies had not have been converted to percentages, discussions like this one would have been avoided.
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​The frequencies in percent makes perfect sense if you understand how those numbers are generated. It's true that no single line can exceed 100% (or "the total is always 1"). However each single line is a separate occurrence from every other line and not dependent on the values of any other line. Given the frequency of each line together with the Numista Rarity index (total number of members who own one or more lines of the coin) one can determine how many members own any individual line of that coin.

Only those that do not have an understanding of how these numbers are generated will consider them nonsense.

Numista Rarity index (total number of members who own one or more lines of the coin)

Now I am very curious about that formula . I had guessed that a rarity index of 97 means there is only one member who has an example of a coin, but how does that play out with increasing numbers of members who have the coin?

For example, how do we get from a 0.2% for the 1997M Proof 10 Markka (which to me means there is a minimum of 410 people who have entered any 10 Markka coin in that table) to a rarity index of 8?

For those not convinced or still don't understand, let's take a simple example:

A coin has 4 year lines, 1999, 2000, 2001, 2002.

Four members (A, B, C and D) have a least one of these coins (NRI~93).
Member A has two 1999s and one 2000.
Member B has one 2000.
Member C has one 1999, one 2000 and two 2001s.
Member D has one 2000.
No member has a 2002.

The frequency for year line 1999 is 2 members out of four = 2/4 = 50%.
The frequency for year line 2000 is 4 members out of four = 4/4 = 100%.
The frequency for year line 2001 is 1 members out of four = 1/4 = 25%.
The frequency for year line 2002 is 0 members out of four = 0/4 = 0%.
Note the doubles that members A and C have do not affect these statistics.

Visually this looks like:

Quote: "tdziemia"​Numista Rarity index (total number of members who own one or more lines of the coin)
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​Now I am very curious about that formula . I had guessed that a rarity index of 97 means there is only one member who has an example of a coin, but how does that play out with increasing numbers of members?
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​I really don't know how the NRI is calculated. I'm not sure anyone does . 97 does mean 1 member and 95 is 2 members but after that I haven't tried to figure out. I read a post awhile ago about it but it didn't help much except something that Idolenz posted where he graphed number of members vs. NRI. I'm posting the graph here and I'll try to find the original post.

I have no problem understanding.

However, I would report frequencies of 0.5, 1.0, 0.25 and 0.

There is no justifcation to multiply each of these by 100% (which is the OP's point, and I tend to agree with that). It is like saying the percent of apples in a population of apple growers.

Edit: Thanks for the graph!

Quote: "tdziemia"​
​For example, how do we get from a 0.2% for the 1997M Proof 10 Markka (which to me means there is a minimum of 410 people who have entered any 10 Markka coin in that table) to a rarity index of 8?
​

​You have to start with the NRI then use 0.2% to calculate the number of members with a 1997M Proof. I don't know how many members NRI of 8 means but for sake of argument (with a very bad extrapolation of the Idolenz curve) let's say it's 2500. Then 2500 X 0.002 = 5 members have a 1997M proof.

That makes sense.

I just found it hard to believe that over 400 members were entering Finland 10 Markka coins. Wow! The hobby is far healthier than I had imagined, and that's a great level engagement with Numista that the creators can be proud of.

Thanks for your explanations. Needless to say, I have a habit of diving into numbers.

Quote: "tdziemia"​I have no problem understanding.
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​However, I would report frequencies of 0.5, 1.0, 0.25 and 0.
​
​There is no justifcation to multiply each of these by 100% (which is the OP's point, and I tend to agree with that). It is like saying the percent of apples in a population of apple growers.
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​Edit: Thanks for the graph!

​We seem to be crossing posts.

That post of the example wasn't meant for you.

I wouldn't argue with reporting frequencies on a 0 to 1 scale. That makes sense to me, too. I would argue (and have I guess) with the notion that the numbers are nonsense because they're on a 0 to 100 scale.

Found it:

https://en.numista.com/forum/topic35822.html

Quote: "cyprusalexander"​So the 9 means digit in date, and not some 9 items.
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​It solves the riddle and make attribution possible.
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​The frequency is a scientific term, out of its definition , the total is always 1, no excuse can change the meaning, thus the existence of nonsense is proved. Solution: either use another word or normalize the numbers, so they will become frequencies: the sum will be 100% and no apologies for writing nonsense, smartly cited already, will be necessary.

​Anyway the two years have each only ONE yearline each, so just use the the year as the biggest difference! Where is the problem?

Quote: "Sjoelund"​​​Anyway the two years have each only ONE yearline each, so just use the the year as the biggest difference! Where is the problem?
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​Some people aren't interested in collecting every year of the issue but are interested in collecting variations in the date font. That makes it useful to specify the date font style used by each year. (And I have no idea if years other than 1993 or 1996 use one style or exist in multiple styles.)