scientific method Flashcards
what are the ethics of planning an investigation?
- Voluntary participation
- Informed consent
- Risk of harm
- Confidentiality
- Anonymity
what is the safety of planning an investigation?
- Risks involved
- safety equipment required
- physical and emotional
what is a placebo
- used to test the effectiveness of medical treatments
- Inactive substance that looks like the real treatment and is administered in the same manner
what group is the placebo given to
the controlled group
what is a single-blind experiment
- occurs when information is withheld from the participant
the researcher knows all the facts
what is a double-blind experiment?
neither the participants nor researchers know who belongs to which group.
Researchers identify each group by analysing the results
high standard if scientific accuracy
easily achieved in drug studies by formulating placebo to have identical appearance to test drug
what is a hypothesis?
it is an “if-then” statement
it includes the dependent and independent variable
a single idea that must be able to be tested
precise an concise
definite statement-no question
what are the different variables
- independent: variable you change
- dependent: variable you measure
- controlled: variable you keep the same
what is validity
- an experiment is considered valid if it tests what is it meant to test.
- for an experiment to be considered valid it must control all variables, excluding the independent variable
- to have a valid experiment you must have reliable and accurate data
what is reliability
- refers to whether an experiment can be repeated by you or any other person who tries the experiment
- an experiment is reliable if it can be repeated with similar outcomes
how is accuracy improved?
- by using the correct equipment
- ensuring the experiment is conducted by an individual with past experience
what are the different types of errors
- systematic error
- random error
- human error
what is a human error?
is a mistake made during an experiment due to a lack of human ability or carelessness
what are random errors?
are unpredictable errors and occur because no measurement is perfect
what is a systematic error
occurs because of the way in which an experiment is designed.
what is the percentage change formula?
new value - old value/old value x 100%
what is the percentage increase formula?
final valve-initial valvue/initial valvue x100
what is extrapolate
extending the graph along the same slope
what is interpolate
predicting data between 2 points
what are the different types of investigations?
observations
controlled experiments
surveys
trail and error
case studies
longitudinal studies
describe observations
the process of using the senses to acquire information
all investigations use observations
scientists look for trends or patterns
describe controlled experiments
a fair test designed to look for relationships between variables
change only one variable, results should be reflective of that change
describe surveys
collect data from a large number of participants
questionnaires or interviews
trial and error
systematic
make one change at a time until the problem has been solved
each trial is recorded-process of elimination
describe case studies
focus on one person or situation
following a group/individual with a certain demographic or disease
describe longitudinal studies
conducted over a few years
a more prolonged case study
build up a picture of change over time
what is the literature review consist of
help define the problem
find out what is already known
assess research methods
allow the researcher to relate findings
what is qualitative data
observations that do not involve numbers
what is quantitative data
data that is expressed in numbers
what group receives the real substance
the experimental group
what is the scientific method?
observation
inferences
hypothesis
experimental design
record and present data
discussion
conclusion
what are the steps in an experimental design
aim- summerise experiment statement
introduction- expand on aim
hypothesis
equipment- including quantity and how much
diagram
procedure/ method- always do procedure first, show how much you are going to do it, the method is the write up after
result- in a form of a table and then put into a graph
discussion- identify patterns and trends in the experiment
conclusion- restate the hypothesis, does the data support the hypothesis, using data
what is repetition
doing the same experiment many times
what is replication
a number if identical experiments running together or at the same time
performing the experiment on a large number of subjects at the same time
what do repetition and replication help to do
helpt to demonstrate that the results are constant
minimise the effects of uncontrolled variables
what is secondary data
is data that is collected by someone else who is not the user of the data
what does secondary data often contain
confidence intervals
what are confidence intervals?
confident intervals indicate the reliability of the data and are expressed as a range of values above and below the results
what are the benefits of a blind experiment?
people involved do not know certain details of experiment
prevents conscious or unconscious bias
how should experiments be designed
so that where possible experiments should be designed so that quantitative data can be collected
can qualitative be given numerical valvues
yes
how can you minimize random errors?
take more data. random errors can be evaluated through statistical analysis and can be reduced by repetition
how can you minimize systematic errors
systematic errors are difficult to detect and cannot be analyzed statistically, because all of the data is off in the same direction. Spotting and correcting for systematic error takes a lot of care
what is an example of a random error
You measure the mass of a ring three times using the same balance and get slightly different values: 17.46 g, 17.42 g, 17.44 g
what is an example of a systematic error
The electric scale you use read 0.05 g too high for all your maths measurements (because it is improperly tared throughout your experiment).
what is the definition of a literature review
a survey of the material that has been written about a subject under consideration
what are outliers
a measurement well beyond the range of other measurements in a set
what are the two types of errors
systematic errors
random errors
what are the different types of random errors
instrument
environment
measurement
human
procedural
provide an explanation and example for each of the different types of random errors
instrument- old (e.g springs are worn out and don’t work)
environment- temperature, humidity, wind
measurement- parallax error (not looking at it straight on), inexperience
human- spilling, stuff ups, dropping items, blunders
procedural- you have the procedure in the wrong steps, adding the chemicals in the wrong place
what is meta analysis
the statistical analysis of a large collection of analysis results from individual studies for the purpose of integrating the findings.
what is a controlled variable
a factor kept the same for both the control and the experimental groups in an experiment
what is an uncontrolled variable
a variable that could not be kept the same for the control and the experimental groups in an experiment
what is safety
the condition of being protected form or unlikely to cause danger, risk or injury
what are ethics
a set of moral principles or values
variable
any factor that may change during an experiment
what is accuracy
how close a measurement is to the true value
average
the total measurements in a group divide by the total number of measurements
outliers
a measurement well beyond the range of the other measurements in a set
median
the mid-point of a set of numbers
range
the difference between the highest and lowest measurements in a group
ratio
a numerical statement of how one variable relates to another
rate
a ratio that shows how long it takes to do something
percentages
a rate, number, or amount in each hundred
percentage change
the relative change between an old value and its new value, expressed as a percentage of the old value
frequency
the number of times an event occurs
what is an inference
a suggested reason why our observation occurred
what are your 5 senses
sight, smell, taste, hearing, touch
where does the independent variable go in a table
the first column
where does the dependent variable go in a table
the last column
where does the dependent variable go in a graph
along the vertical
where does the independent variable go in a graph
along the horizontal
what do you include in your conclusion
restate the hypothesis
explain if your data collected supports the hypothesis of if it doesn’t and the hypothesis is known as a null hypothesis
if the hypothesis is incorrect write it correctly
what is reliability
the extent to which an experiment gives the same result each time it is performed
