Evaluating and concluding

What do good results have to be

Valid, precise, repeatable and accurate

Valid result

You have measured what you are meant to as all variables are controlled

Precise result

The range is small

Repeatable result

You can repeat an experiment multiple times and get the same results

Reproducible result

A different experimenter using different equipment and different methods can obtain similar results

Accurate result

The result is very close to the true value

Error

The difference between your measured value and the true value of whatever your measuring

Systematic error

A consistent difference between the measured values and the true values

What do systematic errors affect

-Accuracy

-Reproducibility

What don’t systematic errors affect

-Validity

-Precision

-Repeatability

How to counter systematic errors

Check the apparatus at the start of the experiment

Random error

When results vary around the true result in an unpredictable way

What do random errors affect

-Validity

-Precision

-Repeatability

-Reproducibility

-Accuracy

How to counter random errors

-Better resolution on apparatus

-Control variables more

-Do more repeats

Conclusion

Explains what the data shows

What are the limitations to a conclusion

-You can only make it if you have valid results

-Limited to the circumstances it was tested under

-Evaluate the quality of your results

-Consider how the experiment could be improved

How to improve precision

Use a computer to collect data