Analysing data, general PAG tips, other Flashcards
What does it mean when you are asked to compare?
Give both similarities and differences
What does it mean you are asked to evaluate or discuss?
Discuss- give both the advantages and disadvantages or a topic
Evaluate- as above, but ensure evidence is given from both sides, and a judgement should be made
How do you decrease the percentage error in biology?
Use equipment with a higher resolution, more graduations
Switching equipment- volumetric flask better than measuring cylinder, graduated pipette better than dropping pipette
What sort of things should you be looking for when you describe data from a graph?
General trends
Giving values from the graph
Do they start and end at the same place, does one continue to increase
Does the difference between the two increase or decrease
Is one close to double another- relative
When comparing growth between time periods what should you compare?
Yearly growth periods, not overall growth
How do you decrease percentage uncertainty?
Use equipment with higher resolution
What are general pag improvments?
Smaller intervals, especially around the range where the most change happens
If no repeats taken, take repeats
Controls- volumes, concentrations, species, temperature, pH…
What does it mean if a PAG is valid?
Control variables have been taken into account, no need to talk about what else to control
If a PAG is valid, how can improvements be made to increase confidence of conclusions?
Carry out many repeats to identify anomalies and reduce the impact of random error via calculating a mean
This also assesses precision and more representative of what you are testing
Calculate range and standard deviations, add to graphs to assess variability e.g if overlap less confidence in data
Perform a statistic test e.g comparing the two means with a t-test, to assess whether there was a significant difference between the two means
What are general plant controls?
Light intensity, and type, and regime
Temperature
Soil type and soil nutrients, pH
Water availability
Humidity
Wind speed
What should you do with an evaluate question?
1 or 2 points supporting the statement- with data from the graph: careful with the wording if means plotted, need to say mean
1 or 2 points disagreeing with the statement, could be from the graph
Then validity:
Larger sample sizes
Statistical tests, and error bars present or overlap
Is what you are measuring a direct measure
Does one sample have a larger sample size
Other factors involved
Presence of repeats
What are things to look out for when evaluating a method?
Sample Size- usually too small
Whether repeats have been carried out
Is there control experiment
How long the experimented lasted
Bias e.g double blind
Control variables- things not taken into account
What are things to look out for when evaluating data?
The overall trend- in all categories
Overlaps of data- whether this is as standard deviation error bars, or data points, and if these are given or not
Is the test group different from the control group. Is the control given
Test-statistic, either T-test or Spearmans to assess whether the difference or correlation is significant
Spread of the data, is there lots at a certain end but not tested for another
Make sure to use the axis given, if mean amount is the axis, needs to be mean
