Unit 3 Flashcards
Investigative biology
Scientific cycle in the correct order
debating ideas and coming up with a hypothesis to test
Researching others work
Designing appropriate experiments
Observing and collecting data from experiments
Analysing data through comparing, interpreting and applying statistics
Evaluating results
Forming conclusions
Refining the original hypothesis
Failure to find an effect (i.e. a negative result) is a ________ finding, as long as an experiment is well ________.
Failure to find an effect (i.e. a negative result) is a valid finding, as long as an experiment is well designed.
Null hypothesis
The null hypothesis is a hypothesis based on the default position, thus that two variables are unrelated.
Rather than setting out to prove hypotheses, scientists often set out to disprove or falsify…………….
Rather than setting out to prove hypotheses, scientists often set out to disprove or falsify null hypotheses
Scientific ideas only become accepted once they have been verified (or alternatives falsified) _________________
Scientific ideas only become accepted once they have been verified (or alternatives falsified) independently
Scientific reports follow a basic format:
Scientific reports follow a basic format:
title; aims and hypotheses; methods; results; analysis of results; discussion and evaluation.
Scientific reports should be written in a manner that allows other scientists to _________ the experiment for verification or further work (________ _________)
Scientific reports should be written in a manner that allows other scientists to repeat the experiment for verification or further work (Peer review)
Peer review
Scientists who specialise in a particular field read reports prior to publication, assessing reliability.
Where the use of animals is unavoidable, the 3Rs are recommended:
Where the use of animals is unavoidable, the 3Rs are recommended:
- Replacement
- Reduction
- Refinement
3Rs- Replacement
Replacement- can the animal be replaced with another? Who decides which animals are acceptable for use and which are not though?
3Rs- Reduction
can fewer animals be used?
3Rs- Refinement
can the procedure be refined to reduce human error?
Scientific investigations are influenced by:
- risk assessments that must take account of that safety of humans or animals involved and any impact on the environment;
- regulation, policy and licensing by governments which aim to limit the potential for the misuse of studies and data;
- funding which can influence the direction and pace of scientific progress.
When using humans, ___________ is essential and subjects must be aware of their right to ___________ their data at any time
When using humans, consent is essential and subjects must be aware of their right to withdraw their data at any time
A pilot study is a……………
A pilot study is a small-scale investigation of a planned research project.
The main aim of a pilot study is to assess ___________ and check ______________/techniques
The main aim of a pilot study is to assess validity and check procedures/techniques
Pilot studies are also known as ‘____________’ studies since they investigate whether a suggested protocol is feasible
Pilot studies are also known as ‘feasibility’ studies since they investigate whether a suggested protocol is feasible
Variables are factors which can be ___________,_____________ or ________________ within an experiment.
Variables are factors which can be changed, controlled or measured within an experiment.
Any scientific experiment will be subject to a series of ___________.
Any scientific experiment will be subject to a series of variables.
An experiment usually has three types of variables
An experiment usually has three types of variables: independent, dependent and confounding.
The independent variable is the variable that is………………………….
The independent variable is the variable that is changed or controlled in a scientific experiment to test the effects on the dependent variable.
The dependent variable is the variable being…………………………
The dependent variable is the variable being tested and measured in a scientific experiment.
confounding variables are…………………….
confounding variables are other variables besides the independent variable may affect the dependent variable
discrete variables are
Discrete variables are distinct and unrelated to each other
Continuous variables have
Continuous variables have a range of values
Quantitative data is
Quantitative data is information about quantities.
Qualitative data is
Qualitative data is information about qualities and often involves descriptions.
A multifactorial experiment involves
A multifactorial experiment involves a combination of more than one independent variable or combination of treatments
An in vitro experiment describes an investigation which is…………………………………
in vitro experiment describes an investigation which is carried out using biological molecules or cells out with their normal biological system (eg. cell culture)
An in vivo experiment describes an investigation which is………………………….
An in vivo experiment describes an investigation which is carried out using a living organism, e.g. mouse model organism.
Observational studies use groups that………………………
Observational studies use groups that already exist to carry out an investigation.
The results of control groups can be used to determine………………………………………………….
The results of control groups can be used to determine if an experiment is working properly at a procedural level and are also used for comparison with treatment results.
A positive control is a treatment that is…………………………………………………………..
A positive control is a treatment that is included to check that the system can detect a positive result when it occurs. This group is expected to have a positive result and proves to the researcher that the experimental design being used is capable of producing results.
A negative control group provides results……………………………..
A negative control group provides results in the absence of a treatment. If a negative control yields an unexpected result this could suggest that there is an unknown confounding variable affecting the experiment and therefore the results would be considered invalid.
To achieve a representative sample group researchers may employ one of three different sampling strategies:
To achieve a representative sample group researchers may employ one of three different sampling strategies:
- random sampling;
- systematic sampling;
- stratified sampling.
In random sampling……………………………..
In random sampling, members of the population have an equal chance of being selected. This reduces the possibility of bias in the sampling group.
In systematic sampling, members of a population are………………………….
In systematic sampling, members of a population are selected at regular intervals. For example members of a population may be listed and every fourth individual selected to form part of the sample group.
In stratified sampling………………………….
In stratified sampling, the population is divided into categories that are then sampled proportionally. This means the population is organised into groups or “strata” according to some characteristic (e.g. age) and the number of individuals sampled from each group is in proportion to the group’s size in the main population.
Precision
The closeness of repeated measurements to one another.
accuracy
A measure of how close the data is to the actual true value.
Validity
Refers to whether conclusions drawn from a set of results are credible. Valid results rely on sound experimental design and execution.
Reliability
Refers to whether a procedure yields consistent results each time it is repeated.
Overall results can only be considered reliable if………………………..
Overall results can only be considered reliable if they can be achieved consistently
An experiment should be repeated as a whole to check……………………………………………..
An experiment should be repeated as a whole to check the reliability of the results.
Procedures
test the aim or hypothesis
Controls
should be present where appropriate in order to determine that any effects are the result of the treatment or show the effect in the absence of a treatment
Controlled variables
the validity of an experiment may be compromised where factors other than the independent variable may have influenced the dependent variable
Sample size
must be large enough to state without bias that any effect on the dependent variable was due to changing the independent variable.
Repetition
experiments must then be repeated in full at a different time using new ingredients to determine reliability
Selection bias
Where individuals, groups or data are not selected randomly, therefore failing to provide a representative sample.
mean
this is the arithmetical average. Add all the values and divide by the number there are.
median
this is the middle point from the range of values. In some cases it may be the same or similar to the mean. If the data is skewed the median may be quite different from the mean.
Mode
this is the most common value in a set of data.
Range
this is the set of values that the data falls into, thus the smallest value to the biggest value and everything in between, e.g. in an experiment where the wing spans of garden birds were measured the range is the smallest wing span to the largest wing span and all wing spans between.
Standard deviation
shows how much variation or spread from the average/mean exists.
Confidence intervals or error bars are indicated in………………..
Confidence intervals or error bars are indicated in tables or on graphs, showing the spread of data around a mean.
Qualitative
Data that is observed
Qualitative
Data that is measured
Any conclusion should refer back to a…………………………
Any conclusion should refer back to a hypothesis, stating whether it should be rejected or not
correlation
when two variables seem to be connected
causation
when changing the independent variable causes the effect noted in the dependent variable
positive correlation
A positive correlation is when an increase in the independent variable seems connected to the increase in the dependent variable.
negative correlation
A negative correlation is when the dependent variable decreases as the independent variable is increased.
A correlation, however, does not always prove that changing the independent variable has directly caused the change in the dependent variable. In short, ………………………………………………………………….
A correlation, however, does not always prove that changing the independent variable has directly caused the change in the dependent variable. In short, correlation does not always indicate causation.
Conclusions should refer back to ……………………………………………
Conclusions should refer back to the original aim and hypothesis.
For conclusions to be valid, the method must be ……………………………………………………..
For conclusions to be valid, the method must be evaluated in terms validity and reliability.
Within the conclusion, the economic, social or environmental impact of the findings should be ________________.
Within the conclusion, the economic, social or environmental impact of the findings should be discussed.
Statistical tests such as t-test may be used to determine whether a result is………………………………….
Statistical tests such as t-test may be used to determine whether a result is significant or merely due to chance.
