statistics - year 1

• measured in C

• average of the hourly temperature readings measured during a 24-hour period

• measured in mm (to 1d.p.)

• includes rain, snow and hail (melted)

• amounts less than 0.05mm are recorded as ‘tr‘ (trace)

• measured in hours (to the nearest tenth of an hour)

• the amount of water vapour in the air

• measured as a percentage of maximum water vapour that could be in the air

• measured in knots (1 knot = 1.15 mph)

• direction is measured in degrees (to the nearest 10)

• measured in knots (1 knot = 1.15 mph)

• direction is measured in degrees (from the north?)

• **beaufort conversion

• measured in dm (decameters/10m)

• the greatest horizontal distance at which an object can be seen in daylight

• measured in hectopascals (hPa)

• small range (~980 to 1035)

• measured in oktas (how many eighths of the sky is covered in clouds)

a whole set of items that are of interest

observes or measures every member of a population

a selection of observations taken from a subset of the population, used to find out about the population as a whole

individual units of a population

a list of sampling units that are individually named or numbered

• random sampling method

• each unit is allocated a unique number and numbers are selected randomly

• numbers can be generated randomly (using a computer) or ‘drawn from a hat’

• random sampling method

• required elements are chosen at regular intervals from an ordered list

• the first item is chosen randomly, the rest chosen at regular intervals from the first (e.g. every 5 items)

• random sampling method

• the population is divided into mutually exclusive strata (e.g under 18s and over 18s) and a simple random sample is taken from each

• the number of samples taken from each strata must be proportional

• non-random sampling

• an interviewer selects a sample that reflects the characteristics of the whole population

• the population is divided into groups (quotas) according to a given characteristic

• the interviewer meets people, assesses their group and allocates them into the appropriate quota

• non-random sampling method

• consists of taking a sample from people who are available at the time, who fit the criteria

data associated with numerical observations

data associated with non-numerical observations

a variable that can take any value in a given range

a variable that can only take specific values in a given range

frequency ÷ class width