Paper 2 - Advanced Info Flashcards
3 advantages of primary data
- collection method is known
- accuracy is known
- you can find answers to very specific questions
2 disadvantages of primary data
- time-consuming to collect
- expensive to collect
4 advantages of secondary data
- easy to obtain
- quick to obtain
- cheap to obtain
- data from some organisations can be more reliable than data you collect yourself
5 disadvantages of secondary data
- method of collection is unknown
- data might be out of date
- data may contain mistakes
- data may come from an unreliable source
- may be difficult to find answers to specific questions
Define simulation
Modelling random real life events to help you predict what could actually happen
Advantage of simulation
It may be easier and cheaper than collecting and analysing real data
What can you use a control group for?
Testing the effectiveness of a treatment
How to carry out an experiment with a control group
Use random selection to select two groups of people. Give the test group the treatment, and give the control group no treatment. Compare the results for the two groups to see how effective the treatment is.
What is a control group?
A group of people selected randomly from the population who are not subject to any factors under the investigation
Define extraneous variables
Any variables that you aren’t interested in but could affect the result of your experiment. You need to try to control these variables during an investigation.
What is a comparative pie chart?
A pie chart where the areas of the pie charts are in the same ratio as the two frequencies
Why use comparative pie charts over pie charts?
Drawing two pie charts the same size to represent them when they have different total frequencies would be misleading
What is the independent variable also known as?
The explanatory variable
What is the dependent variable also known as?
The response variable
When is a scatter diagram an appropriate diagram to use?
When the data is bivariate
What is linear correlation
When the points lie on / near a straight line
How can you draw outliers on a box plot?
Mark them with a X
What type of data do histograms represent?
Continuous, therefore there are no gaps between the bars
4 advantages of the mode
- easy to find
- is always a data value
- can be used with any type of data
- unaffected by open-ended or extreme values
2 disadvantages of the mode
- there may be no mode or sometimes more than one
- it cannot be used to calculate a measure of spread
4 advantages of the median
- easy to calculate
- unaffected by extreme values
- best to use when data is skewed
- can be used to help calculate quartiles, IQR and skew
1 disadvantage of the median
- may not be a data value
2 advantages of the mean
- uses all the data
- can be used to calculate SD and skew
2 disadvantages of the mean
- it’s always affected by extreme values
- can be distorted by open-ended classes
What is the only average that can be found from non-numerical data?
The mode
All outlier equations
> UQ + (1.5xIQR)
< LQ - (1.5xIQR)
> 3SD
< 3SD
What do index numbers show
The rate of change of price over time
What does RPI show
The rate of change of prices in everyday life
What does CPI show
The rate of price changes in everyday life, but does not include mortgage
When is an economy in recession
When its GDP falls in two or more successive quarters
What is quality assurance?
Checking samples to ensure that the product of a manufacturing process meets the required standards
Sample means
A set of sample means will be more closely distributed than the individual values from the same population
How is the mean sample mass distributed?
Normally distributed, therefore 95% of the data lies between the warning limits (2SDs)
What happens if a data point lies outside the action limits on a control chart?
Stop the process and reset the machinery.
What 4 assumptions are made from the peterson capture recapture method?
- the population size has not changed - no births or deaths
- the probability of being caught is equal for all individuals
- marks or tags have not come off
- the sample size is large enough to be representative of the population
What is the absolute risk?
The probability of an event happening
What is the relative risk?
How many times more likely an event is to happen for one group compared to another group
Normal distribution notation
(Mean, variance)
Standard deviation percentages data mean
- 68% lies between one standard deviation
- 95% lies between two standard deviations
- 99.8% lies between three standard deviations
Conditions of a normal distribution
- the data is continuous
- the mean, median and mode are all approximately equal
- the distribution is symmetrical and bell-shaped
How do you calculate the tails of a normal distribution graph?
Left tail = mean - 3SDs
Right tail = mean + 3SDs
How to sketch two normal distributions on the same curve
- the smaller the standard deviation the taller the curve
What is a lab experiment
An experiment conducted in a controlled environment
2 advantages of lab experiments
- easy to replicate
- you can control extraneous variables
Disadvantage of lab experiments
- test subjects may behave differently in test conditions than they do irl
What is a field experiment
An experiment carried out in the test subject’s everyday environment. The researcher controls one or more variables
Advantage of field experiment
- test subject more likely to reflect real life behaviour
2 disadvantages of field experiment
- you can’t control extraneous variables
- harder to replicate the experiment exactly
What is a natural experiment
An experiment carried out in the test subject’s everyday environment where researcher has no control over any variables
Advantage of natural experiment
- more likely to reflect real life behaviour
2 disadvantages of natural experiments
- can’t control any variables
- harder to replicate the study exactly
Data represented by bar charts
Categorical and ordinal
Data represented by histograms
Continuous
