Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Advanced Biology > Experimentation > Flashcards

Experimentation Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What does the term accuracy mean ?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What does the term precision mean ?

A

Measured values are close to each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does reliability mean ?

A

Consistent values in repeats and independent replicates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does validity mean ?

A

Variables are controlled so that any measured effect is likely to be due to the independent variable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a pilot study ?

A

A pilot study is a small-scale investigation of a planned research project.

-They are integral to the development of an investigation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Why do a pilot study ?

A

-To ensure an appropriate range of values for the independent variable.
-Allows evaluation and modification of experimental design.
-Allows one to check techniques
-Help assess validity
-Help plan procedures

In addition, allows establishment of the number of repeat measurements required to give a representative value for each independent datum point.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are variables ?

A

Variables are factors which can be changed, controlled or measured within an experiment.

There are usually three types within an experiment; Independent, dependent and confounding variables.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is an independent variable ?

A

-The variable which is changed in a scientific experiment

-Experiments involve the manipulation of this variable by the investigator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is a dependent variable ?

A

-The variable which is being measured in a scientific experiment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What categories can different types of variables be put into ?

A

Independent and dependent variables can be continuous or discrete

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a discrete variable ?

A

Discrete variables can be grouped

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is a continuous variable ?

A

Continuous variables have a wide range of values that can be measured on a scale between a maximum and a minimum.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a confounding variable ?

A

Any variable, other than the independent variable, which can effect the dependent variable, due to the complexities of biological systems.

These must be held constant if possible, or at least monitored, so their effect on the results can be accounted for in the analysis.

Control of confounding variables help to ensure that investigation results are valid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What happens if you cannot (easily) control a confounding variable ?

A

A randomised block design could be used

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is a randomised block design ?

A

-Experiment subjects are assigned into groups (“blocks”) before being assigned to a treatment group.

-Blocks of experimental and control groups can be distributed in such a way that the influence of any confounding variable is likely to be the same across the experimental and control groups.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does the term treatment mean ?

A

-The treatment refers to the variable being investigated

-The experimental treatment group is compared to a control group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is a simple experiment ?

A

One independent variable only

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is a multifactorial experiment ?

A

Involve a combination of more than one independent variable or combination of treatments.

In general, as experimental designs increase in complexity, more information can be obtained and analysed as welll as allowing the effects of different interactions to be detected

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Discuss the use and limitations of a simple experiment

A

Advantages
-Laboratory conditions can be carefully controlled so allows simple experiments to be conducted more easily than in the field.

Limitations
-The findings may not be applicable to a wider setting.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Discuss the use and limitations of a multifactoral experiment

A

Advantages
-Complex interactions examined and allows generalisations to be made

Limitations
-More complex and time consuming.
-Difficult to control all variables.
-Data analysis is complex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is an observational study ?

A

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

Use of groups that already exist, so there is no truly independent variable

Observational studies are good at detecting correlation, but since they do not directly test a hypothesis, they are less useful for determining causation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the types of correlation ?

A

A positive correlation
-Exists when an increase in one variable is accompanied by an increase in the other variable.

A negative correlation
-Exists when an increase in one variable is accompanied by a decrease in the other variable.

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

23
Q

What is a control ?

A

Are used for comparison with the results of treatment groups

There are two types of controls:
-Positive
-Negative

24
Q

What is a positive control ?

A

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

Positive scientific control groups reduce the chances of false negative results.

Shows how a successful experiment should appear, by a positive result

25
Q

What is a false negative result ?

A

When test results incorrectly indicate the abscence of a condition when it is actually present

26
Q

What is a negative control ?

A

Provides results in the absence of a treatment

Negative scientific control groups reduce the chances of false positive results

Shows how a failed experiment should appear, by a negative result

27
Q

What is a placebo ?

A

Placebos can be included as a treatment without the presence of the independent variable being investigated.

28
Q

What is the placebo effect ?

A

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

29
Q

What is an In Vivo study

A

In vivo refers to experimentation using a whole, living organism

30
Q

What is an In Vitro study ?

A

In vitro refers to the technique of performing
a given procedure in a controlled environment outside of a living organism.

31
Q

What are examples of an In vitro experiment ?

A

1) Cells growing in a culture medium

2) Proteins in solution

3) Purified organelles

32
Q

Describe the progression from In Vitro to In Vivo

A

In Vitro testing using cells in culture may be used as an initial safety test of a new therapeutic compound; however, In Vivo testing using an animal model must be performed before advancing to human clinical trials as this will allow the investigators to assess the performance of the drug within a biological system.

33
Q

Describe advantages and disadvantages of In Vivo studies

A

Advantages
-Provides data for effects in whole organisms.
-Allows study of complex interactions.

Disadvantages
-Expensive and time consuming.
-Ethical and legislative concerns.
-Difficult to control confounding variables.
-Results may be difficult to interpret.
-Difficult to prove causation.

34
Q

Describe advantages of In Vitro studies

A

Advantages
-Simpler and less expensive.
-Easier to control confounding variables.
-Interpretation of results is simpler.
-Can demonstrate correlation and causation.

35
Q

When is a representative sample used ?

A

-Where it is impractical to measure every individual, a representative sample of the population is selected.

-A representative sample should share the same mean and the same degree of variation about the mean as the population as a whole.

36
Q

What determines sample size ?

A

-The extend of the natural variation within a population determines the appropriate sample size.

-More variable populations require a larger sample size (to be reliable)

37
Q

What are the three types of sampling ?

A

Random, systematic and stratified sampling

38
Q

What is random sampling ?

A

Members of the population have an equal chance of being selected

(Names out a hat, computer programme, random name generator)

39
Q

What is systematic sampling ?

A

Members of a population are selected at regular intervals

(Alphabetical list of names, pick every 10th name to be a part of the sample)

40
Q

What is stratified sampling ?

A

The population is divided into categories that are then sampled proportionally

(Group everyone according to height range and proportionally select individuals from each group at random)

41
Q

What may cause variation in experimental results ?

A

Variation in experimental results may be due to the reliability of measurement methods and/or inherent variation in the specimens.

42
Q

How can the reliability of measuring instruments or
procedures can be determined ?

A

-The reliability of measuring instruments or procedures can be determined by repeated
measurements or readings of an individual datum point.

-The variation observed indicates the precision of the measurement instrument or procedure but not necessarily its accuracy.

43
Q

How can the natural variation in the biological material being used be determined ?

A

The natural variation in the biological material
being used can be determined by measuring
a sample of individuals from the population.

-The mean of these repeated measurements
will give an indication of the true value being measured.

-The range of values is a measure of the extent of variation in the results (narrow range = low variation)

44
Q

Why should independent replication be carried out when determining reliability ?

A

-Independent replication should be carried out
to produce independent data sets; Overall results can only be considered
reliable if they can be achieved consistently.

-These independent data sets should be
compared to determine the reliability of the
results

45
Q

What type of data do discrete and continuous variables give rise to ?

A

Discrete and continuous variables give rise to
qualitative, quantitative, or ranked data.

46
Q

What is qualitative data ?

A

Qualitative data is subjective and descriptive.

47
Q

What is ranked data ?

A

Ranked data refers to the data transformation in which numerical values are replaced by their rank when the data are sorted from lowest to highest.

48
Q

What is quantitative data ?

A

Quantitative data can be measured objectively, usually with a numerical value.

49
Q

What has consequences on graphical displays and statistical tests used ?

A

The type of variable being investigated has consequences for any graphical display or statistical tests that may be used.

50
Q

What are boxplots used for ?

A

Boxplots are used to show variation within and between data sets.

51
Q

When does a correlation exist ?

A

A correlation exists when there is a relationship between two variables.

52
Q

What is a correlation ?

A

Correlation is an association and does not imply causation,

53
Q

When does causation exist ?

A

Causation exists if the changes in the values of the independent variable are known to cause changes to the value of the dependent variable.

Advanced Biology (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions