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Maths, Statistics Things To Remember/Large Dataset Questions > Stats > Flashcards

Stats Flashcards

1
Q

Advantages and disadvantages of mode? And what type of measurement is it?

A

Measures Location.
Advantages: Gives most common value and not usually affected by outliers.
Useful for numerical data.
Always is a value from the data set
Disadvantages: Does not make full use of data.
May not be representative as low frequency.
Could potentially be more than one.

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2
Q

Advantages and disadvantages of median, and what type of measurement is it?

A

Measure of location
Advantages: Not affected by outliers and gives middle piece of data
Disadvantages: Can’t be used for non- numerical data.
Not always a value of the dataset
Doesn’t make use of all the data

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3
Q

Advantages and disadvantages of the mean, and what type of measurement is it?

A 
Measure of location 
Advantages: Shows the average value.
Makes use of all the data.
Disadvantages: Affected by outliers and anomalies (for small datasets).
Not always a value from the data set.
Can't be used in non-numerical data.
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4
Q

Advantages and disadvantages of range, and what type of measurement is it?

A

Measure of spread
Advantages: Shows the quantity of data.
Reflects the full dataset.
Disadvantages: Affected by outliers

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5
Q

Advantages and disadvantages of inter-quartile range, and what type of measurement is it?

A

Measure of spread
Advantages: Not affected by outliers
Disadvantages: Doesn’t make use of all the data

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6
Q

Advantages and disadvantages of standard deviation, and what type of measurement is it?

A

Measures spread
Advantages: Makes use of all data, and for large datasets, outliers have a small input.
Disadvantage: For small datasets, outliers have a big impact.

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7
Q

Define population

A

The set of things you are interested in

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8
Q

What is a Census?

A

Observes/measures every member of a population

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9
Q

What is a sample?

A

Subset of population. Used to find info for the whole population. (Bigger=better)

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10
Q

Define statistic? And what are they used for?

A

Value calculated from a sample, e.g mean or standard deviation.
Used to estimate parameters, e.g mean for the sample is an estimate for the mean of a population.
(Sample–> Statistic)

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11
Q

What is a parameter?

A

Number/Value that describes and entire population, such as the mean or standard deviation of the population
(Population–> use parameters)

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12
Q

What is a sampling unit?

A

Individual unit from population,

E.g particular person in UK

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13
Q

What is a Sampling Frame?

A

List of all sampling units in a population

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14
Q

Advantages and disadvantages of a sample over a census

A

Advantages: Quicker and Cheaper.
Less time consuming to process data.
Disadvantages: Less accurate (data may not represent whole population).
Can be biased by choice of sample.

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15
Q

Advantages and disadvantages of a census over a sample

A

Advantages: More accurate, completely unbiased and represents entire population.
Disadvantages: Slower, more expensive and takes longer to process data (lots of units).
Destroy all your population in testing, e.g opening food products to see contents.

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16
Q

Describe Simple Random Sampling

A
  • Get a list of all members in population
  • Number all items in population
  • Use random numbers to select sample and ignore repeats
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17
Q

Describe Systematic Sampling

A
  • Number all items in population
  • Let n=population size/sample size
  • Use a random number from 1 to n to select first item and choose every nth item after that until you have the required sample size
18
Q

Describe Stratified Sampling

A

-Divide population into groups (e.g eye colour, age etc)
-Decide how many to sample from each group with ((number in group)/(number in population)) x sample size
- Use simple random sampling to select items from each group
(When question asks for stratified, describe Simple Random process as well!)

19
Q

What are the Random Sampling Methods?

A

Simple random
Systematic
Stratified

20
Q

What are the non-random sampling methods?

A

Opportunity and Quota

21
Q

Describe Opportunity Sampling

A

Sample consists of any items that are available to be sampled. (This method can also be referred to as convenience sampling)

22
Q

Describe Quota Sampling

A

Population divided into groups and the same proportion of items from each group are included in the sample just like stratified.
Then use opportunity sampling

23
Q

For linear interpolation, for median, what is the equation?

A

Q2-LB/UB-LB = n/2 th value - LF/UF-LF

24
Q

How much data lies within one standard deviations of the mean for a normally distributed variable?

A

68% approx

25
Q

How much data lies within three standard deviations of the mean for a normally distributed variable?

A

Nearly ALL data (99.7%)

26
Q

Describe the 5 UK weather locations in large dataset from North to South

A 
Leuchars
Leeming
Heathrow
Hurn
Camborne
27
Q

In the northern hemisphere, what to months may/June July/September and October represent in the dataset

A

May/June is end of spring
July/September is summer
October is autumn/ beginning of winter.

28
Q

What are the three overseas locations and where are they?

A

Jacksonville (Florida, SE coast USA)
Beijing (East coast of China)
Perth (West coast of Australia)
(Southern Hemisphere)

29
Q

What months and years are measured in large dataset?

A

May to oct for both 1987 and 2015

30
Q

What is the limitation of the large dataset?

A

Only May to Oct and not all year

31
Q

What major events happened that will affect large dataset data

A

Great storm of 1987 UK Oct
Hurricane Floyd 1987 Florida Oct
Hurricane Joaquin 2015 Florida May

32
Q

What is the warmest, coldest, wettest and driest locations in UK from large dataset?

A

Warmest: Heathrow
Coldest: Leuchars (because most nothernly)
Wettest: Camborne
Driest: Heathrow

33
Q

What is the hottest, wettest and coldest locations abroad in large dataset?

A

Hottest/Wettest: Jacksonville

Coldest: Perth

34
Q

What does tr mean and n/a mean in dataset

A

Tr, trace amounts of rainfall, below 0.05 mm

n/a means reading not available/missing data

35
Q

What is 1 knot, 1 hectopascal, 1 decameter

A

1 knot = 1.15mph
1hPa = 100Pa
1Dm = 10m

36
Q

What month is coldest for places in northern hemisphere?

A

October

37
Q

What is qualitative data?

A

Non numerical data, no numbers, e.g Beaufort scale

38
Q

How does Beaufort scale represent windspeed?

A

Low wind: light
Mid wind: moderate
High wind: fresh

39
Q

What percentage is needed for mist and fog to appear for relative humidity

A

Above 95%

40
Q

What data is given for overseas stations

A

Daily mean temp °C
Daily total rainfall mm
Daily mean windspeed knots
Pressure hPa

41
Q

When is it winter in Perth?

A

July to September

Maths, Statistics Things To Remember/Large Dataset Questions (1 decks)

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