Practicals

Question 1

Independent variable

Answer 1

The variable that is changed by the experimenter (you!)

Question 2

Dependent variable

Answer 2

The variable that is measured by the experimenter

Question 3

Control variables

Answer 3

These variables are kept constant to ensure that they do not affect the experiment. (They are never the independent or dependent variable!)

Question 4

Control experiment

Answer 4

Part of an experimental investigation set up to show that the key biological component being investigated is responsible for the changes observed e.g. using a denatured enzyme should produce no results

Question 5

Accuracy

Answer 5

How close the measurement is to the true value

Question 6

Improvements

Answer 6

Refers to how the inaccuracies in the experimental method could be improved e.g. by controlling variables or using more precise equipment

Question 7

Precision

Answer 7

The ability to be exact (degree of precision). Precise measurements are ones which measure something to a very small degree of error (e.g.nearest mm, rather than nearest cm)

Question 8

Reliability

Answer 8

How close together a set of results are in a set of repeated measurements or observations. measurements or observations.

Question 9

Validity

Answer 9

The measure of confidence that can be placed in a set of observations or measurements. Comment on both reliability and accuracy

Question 10

Hazard

Answer 10

An object or chemical and the nature of the hazard

Question 11

Risk

Answer 11

An action in the method that can create a risk from the hazard