Year 1 Stats Chapter 1- Data Collection

Question 1

list of large data set locations

Answer 1

Leuchars - east coast of Scotland
Leeming - (Leeds) north England inland
Heathrow - inland London
Hurn - (southampton) south coast
Camborne - (Cornwall) west coast, highest above sea level
Jacksonville - (Florida) east coast of USA (NH)
Beijing - eastern China near coast (NH)
Perth - west coast of Australia (SH)

Question 2

what is daily mean wind direction and windspeed measured in

Answer 2

direction: bearing or compass
speed: knots and Beaufort scale (1kn = 1.15mph)

Question 3

daily maximum gust units

Answer 3

knots

includes direction from which maximum gust blowing was recorded

Question 4

daily maximum relative humidities units

Answer 4

a % of air saturation with water vapour

above 95% is misty and foggy

Question 5

what is trace in daily total rainfall

Answer 5

amounts less than 0.05 mm (tr)

Question 6

daily mean cloud cover units

Answer 6

oktas

eights of the sky converted by cloud

Question 7

daily mean visibility units

Answer 7

decametres (dm)

greatest horizontal distance an object can be seen in daylight

Question 8

daily mean pressure units

Answer 8

measured in hectopascals

Question 9

daily mean pressure units

Answer 9

measured in hectopascals

Question 10

daily total sunshine units

Answer 10

recorded to the nearest tenth of an hour

Question 11

census

Answer 11

data sets from every member of a population

Question 12

sample

Answer 12

a selection of data sets from a subset of a population

Question 13

population

Answer 13

whole set of items that are of interest

Question 14

less common disadvantages of census

Answer 14

• can’t be used if testing process destroys items (e.g. testing the ripeness of fruit by cutting it in half)
• not possible if population is always changing (can’t obtain accurate sampling frame)

Question 15

less common disadvantage of sampling

Answer 15

sample may not be large enough to give information about small minorities in the subset of the population

Question 16

sampling units

Answer 16

individual units of a population

Question 17

sampling frame

Answer 17

list of all the sampling units, named and numbered

Question 18

define parameter

Answer 18

number used to describe the population

Question 19

test statistic

Answer 19

a number generated through calculation of sampling results

Question 20

what is random sampling

examples

Answer 20

every unit of population has equal chance of being selected

• simple random
• systematic
• stratified

Question 21

what is stratified sampling

Answer 21

• population is split into mutually exclusive strata and a representative random sample is taken
• with the same proportion of each strata in the population, present in the sample

Question 22

less common advantage and disadvantages of stratified sampling

Answer 22

advantage
- accurate reflection of population structure

disadvantage

• may not be account for minorities within strata
• must have clearly classified strata for objective results

Question 23

formula to find stratum within a population

Answer 23

no. of members in strata
————————————- x sample size
total population

Question 24

what is non random sampling

Answer 24

every member of population does not have an equal chance of being selected

• opportunity
• quota

Question 25

what is quota sampling

Answer 25

- population split into strata, and the size of each strata in the sample is in proportion to their size in the population (same as stratified.... THE DIFFERENCE⬇) - an interviewer meets people, assess their strata and allocates them to the appropriate quota - once a quota is filled out, no more people from this strata are interviewed

Question 26

advantages and disadvantages of quota sampling

Answer 26

advantages - no sampling frame needed - can compare different groups easily disadvantages * *- non-random as interviewer chooses who to interview - non responses aren't recorded - splitting population into strata may be time consuming or inaccurate

Question 27

define continuous and discrete data

Answer 27

continuous- can take any value in a given range (measure it) discrete- can only take specific values in a given range (count it)