Unit 3.2b

Question 1

What is a variable?

Answer 1

Any factor that can be controlled, changed, or measured in an experiment

Question 2

What is an independent variable?

Answer 2

The variable that is changed in a scientific experiment

Question 3

What is the dependent variable?

Answer 3

The variable measured in a scientific experiment

Question 4

What is the continuous variable?

Answer 4

Variables with infinite numbers of values
-length, concentration, wavelength

Question 5

What is the discrete variable?

Answer 5

Variables with a finite range of values
-colour

Question 6

What is a simple experiment?

Answer 6

One with only 1 independent variable

Question 7

What is a multifactoral experiment?

Answer 7

Am experiment with many independent variables

Question 8

What’s an advantage of a simple experiment?

Answer 8

The control of laboratory conditions allows them to be conducted more easily, even in the field

Question 9

What is the disadvantage of simple experiments?

Answer 9

The findings may not be applicable to a wider range of settings

Question 10

Why can’t observational studies be used for determining causation?

Answer 10

There is no true correlation

Question 11

What is an observational study?

Answer 11

Study where the independent variable is not directly controlled by the investigator

Question 12

What are confounding variables?

Answer 12

Variables which cannot be altered
Age, gender etc

Question 13

How are confounding variables controlled?

Answer 13

By using randomised block design

Question 14

What is a positive control?

Answer 14

A treatment included that checks that the system can detect a positive result when it occurs

Question 15

What is a negative result?

Answer 15

Provides a result in the absence of a treatment

Question 16

What is a placebo?

Answer 16

It’s a treatment without the presence of the independent variable being investigated

Question 17

What is the placebo effect?

Answer 17

It’s a measurable change in the dependent variable as a result of the patients expectation rather then a change in the independent variable

Question 18

What is a benefit of a placebo?

Answer 18

If someone’s ill taking a placebo releases endorphins

Question 19

Why do researches use placebo?

Answer 19

To see if the drug they are trialling is actually having an effect

Question 20

What is in Vivo?

Answer 20

Experimentation using a whole living organism

Question 21

What is in Vitro?

Answer 21

Performing a given procedure in a controlled environment outside of a living organism

Question 22

What’s an advantage of in vitro?

Answer 22

Better control of the experiment and any confounding variables

Question 23

What’s a disadvantage of in vitro?

Answer 23

Not possible for most biological studies

Question 24

What’s an advantage of in Vivo?

Answer 24

Better idea of what is going on inside the cell or organism

Question 25

What’s a disadvantage of in Vivo?

Answer 25

Living organisms show great variability which can’t really be controlled