Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

A Level - Maths > Statistics - Data collection > Flashcards

Statistics - Data collection Flashcards

1
Q

What is a population?

A

The whole set of items that are of interest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a census?

A

A survey that observes/measures every member of a population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a sample?

A

A selection of observations taken from a subset of a population which is used to find out info about the whole population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the advantage of a census?

A

Should give a completely accurate result

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the disadvantages of a census?

A

Time consuming & expensive
Hard to process large quantities of data
Cannot be used when testing process destroys item

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the advantages of taking a sample?

A

Less time consuming & expensive than a census
Fewer people have to respond
Less data to process

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the disadvantages of taking a sample?

A

Data may not be accurate

Sample maybe not large enough to represent all small sub-groups in the population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What happens as the sample size increase?

A

The more accurate it is

More representative of the sample

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the individual units of a population called?

A

Sampling units

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are done to sampling units in order to distinguish them?

A

They are individually named or numbered to form a list

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a statistic?

A

A value taken from a single sample

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is a sampling frame?

A

A list of the sample units

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What happens in random sampling?

A

Each member of the population has an equal chance of being selected

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the advantages of using random sampling?

A

Representative of the population

Removes bias

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the three methods of random sampling?

A

Simple random sampling
Systematic sampling
Stratified sampling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How can you perform simple random sampling?

A

Number each sampling unit

Random number generator or numbers put into a “hat” and chosen at random

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the advantages of simple random sampling?

A

Free of bias
Easy and cheap for small populations/samples
Each sampling unit has a known/equal chance of selection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the disadvantages of simple random sampling?

A

Not suitable when population/sample size is large

Sampling frame is needed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is systematic sampling?

A

Required elements are chosen at regular intervals from an ordered list
E.g Data taken every nth value

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the advantages of systematic sampling?

A

Simple and quick to use

Suitable for large samples/populations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the disadvantages of systematic sampling?

A

Sampling frame is needed

Can introduce bias if sampling frame is not random

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is stratified sampling?

A

Population is divided into mutually exclusive strata, and a random sample is taken from each
Strata example - male & female

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What rules should be followed for obtaining strata?

A

Proportion of each strata should be the same

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the formula to calculate the number of people should be sampled from each strata?

A

Number sampled in strata = (number in strata / number in population) x overall sample size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What are the advantages of stratified sampling?
Sample accurately reflects the population structure | Guarantees proportional representation of groups within a population
26
What are the disadvantages of stratified sampling?
Population must be clearly classified into distinct strata | Selection within each stratum has disadvantages of simple random sampling
27
What are the two types of non-random sampling?
Quota sampling | Opportunity sampling
28
What is quota sampling?
An interviewer/researcher selects a sample that reflects the characteristics of the whole population
29
How is quota sampling done?
Population is divided into groups by an interviewer due to characteristics Continues until quota is full
30
What happens with quota sample sizes?
Size of each group determines proportion of sample that should have that characteristic Quotas will have a limit - if full the person's data is dismissed
31
What are the advantages of quota sampling?
No sampling frame required Quick, easy and inexpensive Small sample still representative of population Allows easy comparison between different groups
32
What are the disadvantages of quota sampling?
As non-random it introduces bias Population division can be costly or inaccurate Non-responses are not recorded Increases groups so adds time and expensive
33
What is opportunity sampling?
Taking the sample from people who are available at the time the study is carried out and who fit the criteria you are looking for
34
What are the advantages of opportunity sampling?
Easy to carry out | Inexpensive
35
What are the disadvantages of opportunity sampling?
Highly dependent on individual researches | Unlikely to provide representative sample
36
What is opportunity sampling also known as?
Convenience sampling
37
What is quantitative variables/data?
Data/variables associated with numerical observations
38
What is qualitative variables/data?
Data/variables associated with non-numerical observations
39
What is a continuous variable?
A variable that can be given in any range | E.g 2 seconds, 2.3 s, 2.02 s
40
What is a discrete variable?
A variable that can only be specific values | E.g can't have 2.65 people
41
What are the groups in grouped frequency tables called?
Classes
42
What face value data can be found using a grouped frequency table?
``` Class boundaries tell you max and min values in the class Midpoint is the average of the class boundaries Class width is the difference between higher and lower class boundaries ```
43
What large data sets will be provided?
Data about the weather, location, about different places around the world
44
What is the daily mean temperature?
°C | Average of hourly temp readings
45
What is the daily total rainfall?
Includes solid precipitation Melted before being included in measurements Less than 0.05mm recorded as "trace" or "tr"
46
What is daily total sunshine?
Recorded to nearest tenth of an hour
47
What is the daily mean wind direction and windspeed?
Knots, averaged over 24 hours Directions given as bearings & compass directions Mean windspeed also in Beaufort scale
48
What is a knot?
1 kn = 1.15 mph
49
What is the daily max gust?
Highest instantaneous wind speed recorded in knots
50
What is the daily max relative humidity?
% air saturation with water | Above 95% can be misty/foggy
51
What is daily mean cloud cover?
Measured in oktas - eighths of sky covered by cloud | Goes from 0-8
52
What is daily mean visibility?
Greatest distance an object can be seen in daylight | Measured in decameters (Dm)
53
What is daily mean pressure measured in?
Hectopascals (hPa)
54
What is a finite and infinite population?
Finite - can practically be counted | Infinite - cannot be counted practically
55
What is cluster sampling?
Divide population into clusters Randomly select clusters based on sample size Either use all in cluster or randomly sample
56
What are the advantages in cluster sampling?
More practical in some situations | Incorporate other methods into it
57
What are the disadvantages in cluster sampling?
Less representative as only some clusters sampled | Not always possible to separate into clusters in natural ways
58
What is self-selection/volunteer sampling?
People choose to be part of the study after advertisement to whole population Either use all who respond or take sample of them
59
What are the advantages of self-selection sampling?
Little time or effort for sample members Volunteers are less-likely to not respond Could be only way to get people to take part
60
What are the disadvantages of self-selection sampling?
Trends could be present within the population that responds
61
What does n/a mean?
Not available
62
What is 0 on the Beaufort scale?
Calm | Less than 1 knot
63
What is 1-3 on the Beaufort scale?
Light | 1-10 knots
64
What is 4 on the Beaufort scale?
Moderate | 11-16 knots
65
What is 5 on the Beaufort scale?
Fresh | 17-21 knots

A Level - Maths (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions