SOLVED

Keith is studying the variable Daily Mean Wind Direction, in degrees, from the large data set.
Keith summarised the data for Camborne from 1987 into 4 directions A, B, C, and D representing North, South, East and West in some order.
Direction - Frequency
A - 22
B - 48
C - 56
D - 58
(a) Using your knowledge of the large data set state, giving a reason, which direction A represents.
The entry for Hurn on 27th September 1987 was 999.
(b) State, giving a reason, what Keith should do with this value.
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I am bad at stats, and the large data set is my worst nightmare - why is there geography in maths!?!?!?!?
Anyway, I don't even know how to approach this. My teacher's video solution didn't make any sense to me. Anyone got any idea?
(I have the answers btw, I'm looking for genuine help on how to solve this question)

For b) the mean wind direction is
"Daily Mean Wind Direction This value is given in degrees relative to true North. The corresponding cardinal direction is also given. Values are rounded to the nearest 10 degrees. "
https://pmt.physicsandmathstutor.com/download/Maths/A-level/Statistics/Data-Presentation-and-Interpretation-1/Edexcel-Set-B/MA/Data%20Presentation%20and%20Interpretation%20MA.pdf
So 999 is not a valid value. Its likely to be a value representing a data error/unknown value.
a) A,B,C,D represents N,S,E,W in some order and A occurs the least often so the least expected wind direction. West/South winds are the most likely as they come across the atlantic and is our normal weather, and North/East are least likely. Id have thought Easterly winds were the least likely so the likely value for A.

Firstly, thank you so much for the detailed reply. Really helpful.
a) My teacher also said easterly, as 'prevailing winds in the UK are everywhere but East' and that is something expected to know from the data set? Might just have to memorise this.
b) Teacher reason was 'the wind direction is given in degrees, from 0-360, so 999 should be ignored'. I think this question was probably quite openly answered anyway.
Cheers again

They do assume you know some general weather trends to westerly winds are the most common and easterly winds the least. So yes, its one to remember.

Do you know any other little facts like that that just supposed to know? I have been through the textbook chapters, Edexcel guidance booklet, and several website's 'cheat sheets' but they don't always have this stuff on there. Like I'd never seen about the wind before.