How Science Works Flashcards
🔴️Importance of a large number of results
- Anomalies can be identified
- Results are more reliable and representative
- Can use of statistical tests
🔴️Why should a location be selected randomly
- Reduces bias
- Statistical tests can be carried
- More representative data as choice of (x) not influencing data
🔴️Why is it important to check the repeatability of measurements?
- Increases the reliability of measurements
- Anomalies and personal error can be identified
🔴️A scatter diagram can be used to check the repeatability of a test. How?
- Plot appropriate graph
- Points should lie close to the line of best fit
🔴️Why is a statistical test needed?
- The statistical test determines the probability that the results are due to chance
- It allows the null hypothesis to be accepted/rejected
- It determined whether the results are significant
🔴️A statistical test showed that the difference between 2 frequencies of the t allele was significant at the P=0.05 level. Explain
- There’s a 5% probability that the difference in results are due to chance
Explain the advantage of presenting the results as a ratio or ‘Per unit’
- Easier to have a valid comparison
- the sample size may vary
Explain why it was important to grow the ‘plants’ under the same conditions up to ten days before the experiment.
So any difference is due to XYZ
2 advantages of measuring the conc needed to kill 50% of the population in order to determine the effect of a pesticide.
- Provides a standard for comparison of the efficacy of different pesticides
- Does not kill all the tadpoles
Suggest two advantages of carrying out investigations in natural habitats
- Can see effect of other biotic factors e.g predators
- Can see effect of abiotic factors e.g temperature
Advantage of research being conducted by the government’s scientists.
- No bias so it’s trustworthy;
- Non-profit making;
- Focused on advancing environment
How do we treat control groups?
- treat exactly the same but do not give the drug
- give a placebo
- this is done to compare the effect of treatment
- makes sure change in dependent variable is only due to independent variable
What is null hypothesis?
- There is no difference between x and y
- Any difference is due to chance
Reasons why the results of a study may be flawed?
- Small sample size
- Not sure of long-term ramifications
- No repeats
- Bias, not representative
- Not quantifiable results e.g ‘improvement’
Why should the species of animals be kept the same in an experiment
- Similar alleles;
- Controls so genes not a factor
- Only indepents variable affects results
other than cost which factors should be considered when selecting an antibiotic to treat a bacterial disease.
- side effects e.g allergic reactions
- interaction with other drugs
- should only act on the problem bacteria
- how much resistance the bacteria have built up;
Why is measuring rectal temp better than measuring skin temp to find core temp?
- Skin temperature fluctuates more
- As more affected by environment
Why do women outlive men?
- male risk of CVD
- more males smoke and drink to excess
- males involved in war;
why may specific populationsshow very low levels of genetic diversity.
- Population might have been very small (genetic bottleneck)
- Population might have started with small number of individuals (founder effect)
- Inbreeding;
Why is a statistical test important in analysing results
- Statistical test determines the probability of results being due to chance;
- Enables null hypothesis accepted/rejected;
- Determines whether correlation in result is significant;
Explain what accurate and reliable mean
- Accurate means close to the true value
- Reliable means that measurements can be reproduced when repeated to give similar readings
