Working scientifically Flashcards
Name the 3 types of error.
Random, systematic and zero.
What is random error?
Error when your measurements are not the same and the next measurement is unpredictable. Caused by unpredictable changes, e.g. human error, machine’s error, change in environment.
Describe systematic and zero error.
A systematic error is when all your values or readings are too high or too low by the same amount. This could be caused by zero error, when you have not calibrated equipment such as a mass balance to 0, e.g. your mass balance starts at 1g so all your measurements are +1g.
What is an uncertainty?
Your readings are only as good as the equipment you use. For example your thermometer may only have increments of 1 degrees C and your value lies between two temperatures, so you are unsure by + or - 0.5 degrees what the true temperature is.
What is a reproducible?
If someone else repeats your experiment or you do the experiment with different equipment and the results are similar, then your experiment is reproducible.
What is repeatable?
If you repeat the experiment several times and you get the same or similar results then your results are repeatable.
What is the difference between accuracy and precision?
Accuracy - If your results are really close to the true answer.
Precision - If all your results are really close to the mean, not spread out.
Name and describe the different types of variables.
Independent - one that is purposefully changed
Dependent - one you measure the change for based on the independent variable.
Control variable - variables kept the same that could affect the results, helps keep it a fair test.
Describe ways in which accurate data can be obtained.
- Repeat measurements and calculate a mean.
- Repeat measurements with different instruments.
When drawing graphs and charts which variable is on which axis?
x axis - independent
y axis - dependent
What questions should you ask when evaluating an investigation?
- How can the method be improved?
- WWW and EBI
- What is the quality of the data?
- Comment on accuracy, precision, repeatability and reproducibility
