Large Data Set Revision

Most examined · learn first

184 days

1 May – 31 Oct

1987 & 2015

these two years only

locations (5 UK + 3 overseas)

variables

Key fact 1

May–October only. The data only covers May to October (no November–April). So for any "why can't you estimate December / winter" → answer: outside the data range (the LDS only covers May–October).

Key fact 2

Overseas locations have only 4 variables. Beijing / Jacksonville / Perth only have: temperature, rainfall, windspeed, pressure. No cloud cover, sunshine, humidity, visibility or gust. So "why can't you study cloud cover in Beijing" → no cloud cover data for overseas locations.

Key fact 3

Perth is in the Southern Hemisphere. May–October there is autumn → winter, so Perth is the coldest overseas location and the one with the most different weather; Beijing is actually warm during this period.

Data conventions

n/a data not available
tr trace = rainfall < 0.05mm — treat as 0
— a dash for visibility = missing data
The LDS has gaps → this is the answer to "why is the sample fewer than 184 / fewer than expected".

11 variables · name + unit + type

continuous discrete qualitative

Beaufort scale (windspeed)

Windspeed is also given on the Beaufort scale — know the categories (used in questions like "Moderate days"):

0 — Calm — <1 kn
1–3 — Light — 1–10 kn
4 — Moderate — 11–16 kn
5 — Fresh — 17–21 kn

Suitable for a normal distribution?

Sometimes asked: "why is X not suitable to model with a normal distribution?"

Not suitable: Cloud cover (discrete, oktas) · Rainfall (skewed, not bell-shaped) · Pressure (skewed) · Windspeed (not symmetric). Wind direction is qualitative, so it can't be modelled this way either.

8 locations · characteristics

UK 5 UK stations · OVERSEAS 3 overseas (only 4 variables)

UK stations

North → cooler. Leuchars is the most northerly = coldest; Camborne (SW, by the sea) = wettest.

Overseas stations

Only 4 variables each (temperature, rainfall, windspeed, pressure).

Perth sits below the Equator → Southern Hemisphere → seasons reversed (May–Oct = autumn→winter, so it's cold).

Context-question templates · just apply them

Red text must appear or you lose the mark.