Exaggerated representations of the z and t distributions

Uncertainty

To measure the uncertainty associated with a set of results you need to repeat measurements.

Change in theoretical uncertainty with the number of times (n) a single sample is analysed.

How many repeats?

When carrying out any experiment if you only measure two samples you will not know whether one or both are, by random chance, a long way from the ‘true’ value. The better way is to carry out the experiment 5-6 times.

The difference between accuracy and precision.

Accuracy and precision

Accuracy: how close to the “true” value you are (e.g. how close to your true weight your bathroom scales weigh you to).

Example control chart

Repeatable and reproducible

When you are starting out on any set of experiments it is important to know whether the results you achieve on one day will be the same the next. If your results vary daily due to the weather or are sensitive to your mood then you might want to alter your method. In scientific parlance “you need to ensure that your method is repeatable and possibly even reproducible”.

Kawaii signs

On a holiday to Japan I fell in love with all the amazing little pictures on signs. Here are just … More