I manage to find the perfect match for the answer. Thank anyways - BUT still in CoNfUsIoN - is it from the BOOK or the MIND? !!!

The solution is very easy to reach, but the question isHARDto understand clearly, lacking precision maybe.

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My work-out solution on the graph above is WRONG: I divide 30/12 = 2.5 - infact it is referring to 12thvalue not 12 divisions.

QUESTION IS: ESTIMATE THE 12TH HIGHEST SALINITY LEVEL.

so, What Should I understand by that?

1. The 12th highest value could simply be the 12th value of the first 12 values at the beginning of the distribution. ( 12 match with ≈ 10.3)

2. It could be just the highest value of the last top 12 highest values or the highest value of the distribution itself. (30 match with ≈ 15.95)

3. And less likely to be the least value of the last top 12 highest values or the first value of the last top 12 highest values of the distribution

(30 -12 = 18 match with ≈11.4Book Given Answer :!)

Maybe the Question should be : ESTIMATE THE 18th HIGHEST SANITY LEVEL,

or could it be an error in the original question,

or that it is us who is mistaken?

In a hurry, one could have taken any one of these 2 first possibilities as answer, and less likely the 3rd one.

Hope someone else could give the last and best explanation here .

* I suggest you work out that simple statistics question on graph on your own and comment about the answer you get, thank again.