unit 3: investigative biology KA 1-3: Scientific principles and process, Experimentation, and Reporting and critical evaluation of biological research

Question 1

scientific cycle definition

Answer 1

observation; connstruction of a testable hypothesis; experimental design; gathering, recording and analysis of data; evaluation of reults and conclusion; the formation of a revised hypothesis where necessary

Question 2

what is a null hypothesis

Answer 2

the null hypothesis proposed that there will be no statistically significant effect as a result of the experiment treatment

Question 3

what is peer review

Answer 3

specialists with expertise in the relevant field assess the scientific quality of a submitted manuscript and make recommendations regarding its suitability for publication

Question 4

what are review articles

Answer 4

summarises current knowledge and recent findings in a particular field

Question 5

what is a primary paper

Answer 5

a report on the results of an experiment by the person or group who performed it

Question 6

describe the process of peer reveiw

Answer 6

other scientists, who are specialists with expertice in the relavent feild asess the scientific quality of a submitted manuscript & make recomendations regarding its sutability for publication

Question 7

name the 3 R’s that must be considered when conducting animal studies

Answer 7

-reduction
-replacement
-refinement

Question 8

what does reduction mean when conducting animal studies

Answer 8

reduce the number of animals in a study (without compromising the alidity or reliability)

Question 9

what does replacement mean when conducting animal studies

Answer 9

avoid using animals when an alternitive cellular module system exists

Question 10

what does refinement mean when conducting animal studies

Answer 10

techniques should be adjusted to minimise harm to animals

Question 11

name the key points that must be followed when conducting human studies

Answer 11

-confidentiality
-the right to withdraw data
-informed consent (do they agree to take part and do they know what possible consequences could be)

Question 12

what does the term valididty mean

Answer 12

variables controlled so that any measured effect is likely to be due to the independant variable

Question 13

what does the term reliability mean

Answer 13

consistent values in repeats and independant replicates

Question 14

what does the term accuracy mean

Answer 14

data, or means of data sets, are close to true value

Question 15

what does the term precision mean

Answer 15

measured values are close to each other

Question 16

what is a pilot study

Answer 16

a small scale study conducted to refine values for independent and controlled variables prior to conducting an experiment

Question 17

what is an independent variable

Answer 17

an independent variable is the variable that is changed in a scientific experiment

Question 18

what is a dependant variable

Answer 18

a dependant variable is the variable that is being measured in a scientific experiment

Question 19

what is a discrete variable

Answer 19

the measurements fall into distinct groups/dont have a unit- ie blood type, yes/no, left/right, eye colour, hair colour

Question 20

what is a continuous variable

Answer 20

measurements have a range of values between a minimum and maximum/have a unit- ie height, temperature, time

Question 21

name the two types of studies

Answer 21

experimental and observational

Question 22

what is an experimental study

Answer 22

an experiment that involves the manipulation of the independent variable by the investigator

Question 23

what is a randomised block design

Answer 23

an experiment in which treatment and control groups can be distributed in such a way that the influence of any confounding variables are likely to be the same across the treatment control groups

(example- splitting up the groups into males and females before splitting again into the treatment and control groups)

Question 24

what is a negative control

Answer 24

provides results in the absence if treatment

Question 25

what is a positive control

Answer 25

a treatment that us included to check that the system or equipment can detect when positive results occur

Question 26

define the placebo effect

Answer 26

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

Question 27

definition of an in vitro study

Answer 27

preforming a given procedure in a controlled environment outside if a living organism (cells growing in culture or proteins in solution)

Question 28

definition of an in vivo study

Answer 28

experimentation using a whole, living organism (a drug trial or environmental sampling)

Question 29

advantages of an in vitro study

Answer 29

-can be tightly controlled -this permits the use of simple experiments with clear & accurate findings

Question 30

disadvantages of an in vitro study

Answer 30

the findings may not be applicable in a wider setting

Question 31

advantages of an in vivo study

Answer 31

more true to life than studies done in a lab

Question 32

disadvantages of an in vivo study

Answer 32

-more complex to account for the wider range of confounding variables -the independent variable is often not under direct control & there is almost always something that cannot be controlled

Question 33

describe the random sampling method

Answer 33

members of the population have an equal chance of being selected

Question 34

describe the systematic sampling method

Answer 34

members of the same population are selected at regular intervals

Question 35

describe the stratified sampling method

Answer 35

the population is divided into categories that are then sampled proportionately

Question 36

what is selection bias

Answer 36

the selection of a sample in a non-random way, so that the sample is not representative of the whole population

Question 37

describe how selection bias can be avoided when sampling

Answer 37

By sampling populations randomly

Question 38

what do box plots not have

Answer 38

error bars and the mean

Question 39

what is a positive corelation

Answer 39

where an **increase** in one variable is accompanied by an **increase** in another variable

Question 40

what is a negative corelation

Answer 40

where an **increase** in one variable is accompanied by an **decrease** in another variable

Question 41

describe a strong and weak correlation

Answer 41

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

Question 42

define a statistically significant result

Answer 42

a result that is unlikely to be due to chance alone

Question 43

how could you tell if a result was statistically significant from the error bars alone

Answer 43

if the error bars **do not** overlap, then the results are significantly different. if the error bars **do** overlap, then the results are not statistically significant