expirimental design

Question 1

what is inductive reasoning + example

Answer 1

process of inferring a general law or principle from observation of a particular instance
cognitive dissonance

Question 2

what is deductive reasoning + example

Answer 2

inference by reasoning from a general principle to a particular situation

Question 3

describe the different stages in the scientific method

Answer 3

question->hypothesis->experiment->analyse data->draw conclusions-> impact of data: model may be strengthened, modified

Question 4

experimental control?

Answer 4

all things the same EXCEPT the test variable

Question 5

4 obstacles to overcome

Answer 5

perfectly definite change and do nothing else to influence result
biologic variability
chance; experimental errors, faults in methods, differences in reagents
bias in experimenter and experimental design

Question 6

randomised…

Answer 6

subjects are assigned to either treatment or control groups in a random fashion

Question 7

double-blind

Answer 7

subjects arent aware of the treatment they’re receiving and neither is the investigator

Question 8

single blind

Answer 8

subjects arent aware of the treatment but the experimenter is
potential for bias

Question 9

placebo controlled

Answer 9

a false treatment is necessary to measure the proportion of any observed effect accountable to the placebo effect

Question 10

cross over

Answer 10

subjects are swapped over from the treatment to control group. assumes that the effects of the drug are completely reversible

Question 11

matching or randomised block design

Answer 11

subjects matched for age, sex, weight, stage of life
extend observation to a number of groups. with replication and randomisation of treatments, the error from variation is made to fall equally on treated and untreated groups

Question 12

what overcomes biological variability and chance

Answer 12

biologic variability and chance overcome with replication

Question 13

why used statistics

Answer 13

overcome variation in natural systems by analysing whether a difference can be ascribed to chance events
data can be organised, analysed and compared
enable hypothesis to be testes

Question 14

what do we need samples to be

Answer 14

representative of the entire population for valid conclusions to be drawn
too small; inaccurate
too large; costly and inefficient

Question 15

what reduces chance of bias

Answer 15

randomisation, replication, blinding and placebo

Question 16

what does matching reduce

Answer 16

effect of known variability