3.2

Question 1

pilot study

Answer 1

a preliminary small scale study conducted to help decide how best to conduct a large scale research project.

Question 2

independent variable

Answer 2

variable that is changed or controlled in a scientific experiment

Question 3

dependent variable

Answer 3

variable tested and measured in a scientific experiment

Question 4

confounding variable

Answer 4

variable which affects the dependent variable that is not the independent variable

Question 5

continuous variation

Answer 5

characteristic that can be measured and it shows a wide range occurring between two extreme measurements

Question 6

discrete variation

Answer 6

characteristic that shows a definite number of easily observed clear-cut types

Question 7

quantitative data

Answer 7

data that is measured (eg. numbers)

Question 8

qualitative data

Answer 8

data that is observed (eg. colour)

Question 9

ranked data

Answer 9

observations put in order from smallest to largest

Question 10

positive control

Answer 10

treatment that is included to check that the system can detect a positive result when it occurs

Question 11

negative control

Answer 11

provides results in the absence of a treatment

Question 12

precision

Answer 12

the closeness of repeated measurements to one another

Question 13

accuracy

Answer 13

a measure of how close the data, or means of data sets, are are to the true value

Question 14

validity

Answer 14

all confounding variables controlled so that any measured effect is likely to be due to the independent variable.

Question 15

reliability

Answer 15

consistent values in repeats and independent replicates

Question 16

in-vivo

Answer 16

an investigation carried out using a living organism e.g. mouse model organism

Question 17

in-vitro

Answer 17

an investigation carried out using biological molecules or cells out with their normal biological system e.g. cell culture

Question 18

simple experimental design

Answer 18

experimental design where only 1 independent variable is changed at a time

Question 19

multifactorial experimental design

Answer 19

experimental design is more complex and involves a combination of more than one independent variable or combination of treatments

Question 20

randomised block

Answer 20

minimise the effects of when confounding variables cannot easily be controlled

Question 21

observational studies

Answer 21

the independent variable is not directly controlled by the investigator, for ethical or logistical reasons

Question 22

causation

Answer 22

when changing the independent variable causes the effect noted in the dependent variable

Question 23

representative sample

Answer 23

should share the same mean and the same degree of variation about the mean as the population as a whole

Question 24

stratified sampling

Answer 24

the population is divided into categories that are then sample proportionally

Question 25

random sampling

Answer 25

members of the population have an equal chance of being selected

Question 26

systematic sampling

Answer 26

members of a population are selected at regular intervals

Question 27

placebos

Answer 27

placebos can be include as a treatment without the presence of the independent variable being investigated

Question 28

placebo effect

Answer 28

a measurable change in the dependent variable as a result of a patient’s expectations, rather than changes in the independent variable.

Question 29

box plots

Answer 29

used to show variation within and between data sets

Question 30

mean

Answer 30

the arithmetical average, add all values and divide by the number there are of them

Question 31

median

Answer 31

the middle point from the range of values

Question 32

mode

Answer 32

the most common values in a set of data

Question 33

correlation

Answer 33

a connection between the variables and does not imply causation

Question 34

strength of correlation

Answer 34

is proportional to the spread of values from the line of best fit

Question 35

positive correlations

Answer 35

exists when and increase in one variable is accompanied by an increase in the other variable

Question 36

negative correlations

Answer 36

exists when an increase in one variable is accompanied by a decrease in the other variable