Unit 3

Question 1

replacement

Answer 1

avoiding using animals

Question 2

reduction

Answer 2

using fewer animals

Question 3

refinement

Answer 3

change the way the experiment is carried out so animals suffer as little as possible

Question 4

pilot study

Answer 4

small scale investigation of a planned research project used to help

• develop and/or practice protocols in order to ensure validity of experimental design
• check effectiveness of techniques
• find a suitable range of values for the independent variable
• identify and control confounding variables
• identify suitable numbers of replicates

Question 5

types of variables

Answer 5

independant- variable that is changed or controlled
dependant- variable that is being tested or measured
confounding- any factor that affects dependent variable that isn’t independent- must be held constant or monitored

Question 6

randomised block design

Answer 6

used in cases where confounding variables can’t easily be controlled, blocks or experimental and control groups can be distributed in such a way that the influence of any confounding variable is likely to be same across all groups

Question 7

what types of data can discrete or continuous variables give rise to?

Answer 7

quantitative, qualitative or ranked data

Question 8

limitations and use of simple (one independent variable) experimental design

Answer 8

findings may not be applicable to wider setting, control of lab conditions means that these experiments can be conducted more easily than in the field

Question 9

multifactorial experimental design

Answer 9

more than one independant variable

Question 10

in vivo

Answer 10

carried out using living organisms, tend to be more complex than in vitro experiments

Question 11

in vitro

Answer 11

carried out using biological molecules outwith normal biological system ie. cell culture

Question 12

observational studies

Answer 12

studies where there is no independent variable, good at detecting correlation but as they don’t directly test the model, not useful for determining causation

Question 13

control groups are used for

Answer 13

comparison with treatment results

Question 14

negative control

Answer 14

provides results in the absence of a treatment

Question 15

positive control

Answer 15

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

Question 16

when is a representative sample of the population selected?

Answer 16

where it is impractical to measure every individual

Question 17

what determines appropriate sample size?

Answer 17

extent of natural variation within a population, more variable= larger sample size

Question 18

a representative sample should share the

Answer 18

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

Question 19

random sampling

Answer 19

members of the population have an equal chance of being selected

Question 20

systematic sampling

Answer 20

members of a population are selected at regular

intervals

Question 21

stratified sampling

Answer 21

population is divided into categories that are then

sampled proportionally

Question 22

reason for variation in experimental results

Answer 22

due to reliability of measurement methods and/or inherent variation in the specimens

Question 23

how to determine the reliability of measuring instruments or procedures

Answer 23

by carrying out repeated measurements or readings of an individual data point, the variation observed indicates the precision of the measurement instrument or procedure but not necessarily its accuracy

Question 24

how can natural variation in biological material used be determined?

Answer 24

by measuring a sample of individuals from the population- mean of these repeated measurements will give an indication of the true value being measured

Question 25

repeating experiements checks

Answer 25

reliability of results

Question 26

scientific cycle

Answer 26

construction of a testable hypothesis, experimental design, gathering, recording, analysis of data, evaluation of results, conclusions and the formation of new hypotheses where necessary

Question 27

null hypothesis

Answer 27

hypotheses stating that one variable will have no effect on the other

Question 28

why should publication of methods, data, analysis and conclusions in scientific reports be reported in standard format and in detail?

Answer 28

so that others are able to repeat the experiment

Question 29

review articles

Answer 29

summarise current knowledge and recent findings in a particular field

Question 30

what do scientific ideas need before being published?

Answer 30

independent verification and must be supported by similar findings in a number of other investigations

Question 31

all findings are subject to critical evaluation from

Answer 31

peers in peer review and the public through the wider media

Question 32

integrity and honesty in scientific literature

Answer 32

unbiased presentation of results, citing and | providing references, avoiding plagiarism

Question 33

when using humans what should be ensured?

Answer 33

informed consent and subjects must be aware of the right to withdraw data and confidentiality

Question 34

what can influence scientific research?

Answer 34

legislation, regulation, policy and funding

Question 35

Scientific reports should contain

Answer 35

an explanatory title, a summary including aims and findings, an introduction explaining the purpose and context of study including the use of several sources, supporting statements, citations, and references, method section containing sufficient information to allow another investigator to repeat the work

Question 36

Experimental design should test

Answer 36

the intended aim or hypothesis

Question 37

what should treatment effects be compared to

Answer 37

controls and any confounding variables

Question 38

what is necessary to ensure representative sampling and allow the investigator to show that altering the independent variable has, in fact, had an effect on the dependent variable?

Answer 38

a large and unbiased sample group

Question 39

how is data usually presented?

Answer 39

as tables and graphs, with statistical analysis used as appropriate

Question 40

statistical analysis

Answer 40

median, mode, mean

Question 41

standard deviation

Answer 41

used to assess the spread of the data

Question 42

what type of results are unlikely to be due to chance alone?

Answer 42

statistically significant results

Question 43

what do confidence intervals and error bars suggest?

Answer 43

variability of data around a mean, if the treatment average differs from the control average sufficiently for their confidence intervals not to overlap then the data can be said to be different

Question 44

conclusions should refer to

Answer 44

aim, results and hypothesis and existing knowledge and the results of other investigations

Question 45

what should be taken into account to decide if conclusions are valid?

Answer 45

validity and reliability of experimental design, may include discussing controlled variables, sample size, repetition and accuracy of measurements

Question 46

what should consideration be given to pertaining results?

Answer 46

whether the results can be attributed to correlation or causation