Stats

Question 1

Discrete data is:

Answer 1

Data with a specific value e.g. age or shoes size

Question 2

Continuous data is:

Answer 2

Data that can have any value within a specific range e.g. foot length (time can be either)

Question 3

Population is:

Answer 3

Whole set of the thing you’re interested in

Question 4

Sample is:

Answer 4

Subset of the thing you’re interested in

Question 5

Pros and cons of sample (instead of population)

Answer 5

Pros: quicker, faster, cheaper. Cons: might not represent full population, may introduce bias

Question 6

Sampling frame is:

Answer 6

list of all members of a population

Question 7

Population parameter is:

Answer 7

numerical value describing a characteristic of the population

Question 8

Random sampling

Answer 8

Every member of a group has an equal chance of being selected

Question 9

Pros of random sampling

Answer 9

Free of bias, easy & cheap for small samples & populations. Each sampling unit has a known an equal chance of selection.

Question 10

cons of random sampling

Answer 10

Not suitable for large samples& populations. sampling frame needed

Question 11

Systematic sampling

Answer 11

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

Question 12

stratified sampling

Answer 12

The population is divided into mutually exclusive strata (e.g men and women), random sample is taken from each

Question 13

advantages of systematic sampling

Answer 13

Simple and quick to use. suitable for large samples and large populations

Question 14

advantages of stratified sampling

Answer 14

Sample accurately reflect population structure. proportional representation of group with population

Question 15

disadvantages of systematic sampling

Answer 15

Sampling frame is needed. bias introduced if sampling frame is not random

Question 16

non-random sampling: quota sampling

Answer 16

An interviewer or research selects a sample that reflects the characteristics of the whole population

Question 17

non-random sampling: opportunity sampling

Answer 17

taking the sample from people who are available at the time of the study is carried out and who fit the criteria you’re looking for

Question 18

advantages of quota sampling

Answer 18

Allows a small sample to still be representative of the population. no sampling frame needed. quick, easy & inexpensive allows for easy comparison between different different groups with an a population

Question 19

disadvantages of quota sampling

Answer 19

Non-random sampling can introduce bias. population must be divided into groups which can be costly or inaccurate, increasing scope of study increases number of groups which adds time and expense, non responses are not recorded as such

Question 20

advantages of opportunity sampling

Answer 20

Easy to carry out, inexpensive

Question 21

disadvantages of opportunity sampling

Answer 21

Unlikely to provide a representative sample, highly dependent on individual researcher

Question 22

daily mean temperature

Answer 22

measured in C, average hourly temperature readings during 24h period

Question 23

Daily total rainfall

Answer 23

Including snow and hail (melted before inclusion), amounts less than .05mm recorded as tr or trace

Question 24

Daily total sunshine

Answer 24

recorded to nearest tenth of an hour

Question 25

Daily mean wind direction & windspeed

Answer 25

in knots, averaged over 24hrs from midnight to midnight. wind direction given as bearings and compass directions. categorised in Beaufort scale

Question 26

Daily maximum gust

Answer 26

in knots, highest instantaneous windspeed recorded, direction is also recorded

Question 27

Daily maximum relative humidity

Answer 27

given as percentage of air saturation with water vapour, about 95% rise to misty and foggy conditions

Question 28

Daily mean cloud cover

Answer 28

measured in ‘oktas’ or eighths of sky covered by cloud

Question 29

Daily mean visibility

Answer 29

measured in decameters (Dm), greatest horizontal distance which an object can be seen in daylight

Question 30

Mean

Answer 30

the average calculated using formula: Sum of X / number of values

Question 31

Mode

Answer 31

value that occurs the most often in a data set

Question 32

Median

Answer 32

middle value when data is in order of size