Mark Scheme Flashcards
Do the results support the hypothesis?
- Yes/No valid statement
- Refer to a pattern
- Use an example from results which is not an anomalie
Did you get any anomolous results?
- Yes/No valid statement
- Anomalous results are results that do not follow the observed or expected pattern.
- Give an example. Say that some results strayed too far from the line of best fit on the graph.
Describe in detail how you could use repeated readings to obtain an accurate result.
- Calculate the mean.
- Do this by adding the results together and dividing by the number of results.
- Discard anomalies before taking the mean.
What was your range? Was your range suitable?
- State range. INCLUDE UNITS.
- Explain whether or not range was suitable. A yes answer could be that most people are in this range of heights. It could also be because there was a perceptible difference between the values of the dependant variable. It was enough to see a clear relationship.
State the independent, dependant and a control variable.
- The independent variable in this case was height.
- The dependant variable was volume of air displaced.
- A control variable would be age.
INCLUDE UNITS JUST TO BE SAFE
What are variables?
- Variables are physical, chemical or biological quantities or characteristics involved in an experiment.
What was the biggest cause of error or uncertainty? How would you reduce it in future?
- Identify suitable error or uncertainty.
- Suggest a way of reducing the error/uncertainty.
- Explain how the way suggested will reduce error/uncertainty.
In this case: a cause of error was gender. To reduce the impact of this, in future, take separate experiments for males and females and view their data separately. This will reduce error because gender will no longer influence lung volume (males have a larger average lung volume because they have more muscle mass and increasing muscle mass increases oxygen demand significantly.)
Draw a sketch graph.
- Label axes.
2. Show correct relationship.
Explain whether or not the results in case studies 1, 2 and 3 support the hypothesis.
- Correct statement for 1, 2 and 3.
- Give detailed explanations for 2 of them.
- Support with quantitative data.
- Briefly reference the limitations of one case study.
To what extent do the results in case study 4 support the hypothesis you were given / to what extent do you agree with the company’s advice?
- Simple statement.
- Reference to qualitative pattern/trend.
- Back with quantitative data.
- Discuss clear advantage (summative assessment of success).
- Discuss clear disadvantage (summative assessment of success).
Look at every piece of information, not just the data. - Discuss the extent of the pattern. [For example, positive correlation until the peak at x value, after which the correlation is negative.]
Relate your experiment to the context.
- Idea
- Explanation
- Detail
(In this case: the more water is displaced, the greater the lung capacity. This means that the student has more natural ability to play a wind instrument, which requires a high lung capacity in order to avoid squeaking. The wind teacher can therefore reccommend playing a wind instrument for students who do have high lung capacities and suggest another instrument to those who did not.)
What was the resolution of the equipment you used?
Do you think that the resolution was appropriate for the investigation?
- 500ml - measuring jug
1mm - metre rule - Statement of whether or not the range was suitable, backed by explanation.
[The resolution of the measuring jug was not suitable. Its resolution was far too numerically high and meant that values in between the 500ml intervals would have to be estimated. This increased uncertainty and created anomalies due to measurement error. Changing the resolution by calibration to be smaller would have had a significant impact on results.]
Did you repeat any of the results in your investigation? Explain why you did or did not repeat the results of your investigation.
- State correctly whether repeated or not repeated.
- State which values were repeated.
- Refer to anomalous results, and the effect of random, systematic and measurement error.
[We did not repeat any results. No value was repeated. This was because measuring height has a very small uncertainty, however water displaced should have been repeated because, due to large resolution, uncertainty is presumably very high. This means that systematic and measurement error has a bigger effect on the accuracy of results and anomales are very likely.]
If you had to choose another value for this variable, either within or outside this range, what value would you have chosen?
- [State range]
- Suggest another appropriate value for the independent variable.
- Make a clear reason for this additional value.
[Another appropriate value would have been x. This is because the interval between the independent variable was not consistent and more results were needed around this area, in order to make the pattern more apparent.]
You have been given a set of results obtained by other people.
Do these results other results show that this investigation is reproducible?
Explain your answer using examples from the results.
- State whether or not the other results support the pattern of the candidate’s results.
- A reproducible investigation is an investigation in which other people who use the same / different method and equipment obtain the same results.
- Identify a common pattern.
- . Use two examples from the other results.
