Testing Etc

Question 1

Fair test?

Answer 1

A fair test is when you only change one thing (the independent variable) in your experiment.

Question 2

Reliability?

Answer 2

Reliability means that the same (or very close) results will be achieved each time the experiment is carried out by anyone.

Question 3

How can you make sure that something is reliable?

Answer 3

Make sure that you have a large sample size and you generate lots of data.

Question 4

Validity?

Answer 4

Validity means that you can compare your results and make predictions with the confidence of knowing you have done a good job.

Question 5

How can you make sure that results are valid?

Answer 5

It must be a fair test if you want the results to be valid.

Question 6

Accuracy?

Answer 6

An investigation is accurate when the apparatus is set up properly, readings are taken correctly and apparatus which are sensitive enough to measure to measure what you need are used, all to ensure that your results are precise and correct.

Question 7

Odd results?

Answer 7

Odd results are results that may not ‘fit in’ with the other data you have collected.

Question 8

How to reduce odd results?

Answer 8

To reduce the significance of this result on the rest of your data , experiments must:

• be repeated
• have an average calculated

Question 9

Precision?

Answer 9

Precision is when everything such as measurements are done correctly and exactly. Precision is key, along with accuracy, to getting valid and reliable results.

Question 10

Writing methods?

Answer 10

• recorded in enough detail that it can be repeated by someone else to get the same result
• written in numbered point form
• written in the third person
• must contain correct names for common laboratory equipment
• must include all necessary information, measurements, volumes and masses of the chemicals that may be used
• must not contain unnecessary or unimportant information