Here are some key HSW terms we’ll use

Here is a list of key terms that we’ll be refering to

You really should try to familiarise yourselves with them so that as your studies progress you can use them in a real context.

Term Explanation
Accurate A measurement that is close to the true value.
Anomalous data Measurements that fall outside of the normal or expected range of measured values. Biological variation makes identification of anomalous values difficult, but sampling large numbers allows them to be identified more easily.
Causal link, or causation A change in one variable that results from (or is caused by) a change in another variable.
Chance The result of an investigation could have a genuine scientific explanation or be due to chance. Scientist use statistical tests to assess the probability that a result is due to chance.
Correlation A correlation shows a relationship between two variables. Evidence of correlation does not automatically imply causation.
Dependent variable The variable measured for each change in the independent variable.
Errors Errors cause a reading to differ from the true value.
Evidence Data or observations that are used in support of a hypothesis or belief.
Fair test A test in which only the independent variable has been allowed to change the dependent variable, i.e. one where all other variables are controlled.
Hypothesis A possible explanation of a problem that can be tested experimentally.
Independent variable The variable that is changed by the investigator.
Null hypothesis A hypothesis that is worded in terms of there being no difference or association (the negative version of a hypothesis).
Precision Precise measurements are ones which have little spread about the mean value.
Probability The likelihood of an event occurring. It is different from chance because it can be expressed mathematically.
Random distribution These arise as a result of chance. Data will only be valid if collected randomly as this avoids bias and allows a statistical testing.
Reliability The ability to repeat the results of an investigation. Reliability can be improved by taking more measurement or repeating the experiment many times.
True value The accurate true value that can be found if measurements are taken with no errors.
Validity Data are valid if they are made by the effect of a single independent variable.
Valid conclusion A conclusion that can be drawn if supported by reliable data measured by precise instruments to an acceptable degree of accuracy.

About chemicalguy

I'm a former research scientist, lecturer, examiner and chemistry & biology tutor. I now write A-level chemistry and biology text books full time to fill the current gaps in the market.
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