NESA Biology Conducting Investigations
2 sample questions with marking guides and sample answers · Avg. score: 100%
Students designed a controlled experiment. After they had performed the experiment, another group of students gave them feedback suggesting that they should modify the experiment to improve the accuracy of their results.
A change that the first group of students could make to improve the accuracy of their results could include
ignoring outlying results.
repeating the experiment many times.
carefully calibrating the equipment used.
having many people take the measurements.
Reveal Answer
ignoring outlying results.
Ignoring outliers does not improve accuracy and can lead to biased results; outliers should be investigated to understand their cause rather than simply discarded.
repeating the experiment many times.
Repeating the experiment many times improves the reliability and precision of the results, but it does not correct systematic errors that affect accuracy.
carefully calibrating the equipment used.
Carefully calibrating equipment reduces systematic errors, ensuring that the measurements are as close to the true value as possible, which directly improves accuracy.
having many people take the measurements.
Having multiple people take measurements introduces human variability and potential error, which can decrease precision without improving accuracy.
A student designed and conducted a practical investigation to test for the presence of microbes in water and food samples.
Justify a safety precaution required to prevent infection when conducting the investigation.
Reveal Answer
The wearing of gloves to prevent contact with skin and the subsequent entry of pathogens into skin/mouth
| Descriptor | Marks |
|---|---|
Justifies a safety precaution used to prevent infection | 2 |
Provides some relevant information | 1 |
None of the above | 0 |
Explain how the student could ensure the reliability of the investigation.
Reveal Answer
The student could repeat the experiment by using five plates to culture the same sample of food or water. This would mean the student could check that the results are similar in each test.
| Descriptor | Marks |
|---|---|
Explains how to ensure the investigation is reliable | 2 |
Provides some relevant information | 1 |
None of the above | 0 |