Scientific Method Flashcards
Define primary data.
Data that you have measured or collected yourself.
Define secondary data.
Data or information that has been collected by someone else.
Define valid data.
Results that are affected by only a single variable.
Are reproducible.
Define reliable data.
Highly likely to be true.
A trustworthy source of information.
Reproducible data.
Define sample size.
The number of individual pieces of data collected in a survey.
Define research ethics.
The ethics of planning, conduct and reporting of research.
Define risk assessment.
Assesses the severity of a risk associated with the investigation.
Define prediction.
A statement about a future event.
A guess sometimes based on facts or evidence.
Define hypothesis.
A tentative prediction, usually based on an existing model or theory.
Define independent variable.
A variable upon which another variable depends; usually the dependant variable.
Define dependant variable.
A variable that changes as a result of changes to the independent variable.
Define controlled variable.
The variable that is controlled by the experimenter.
The variable that you keep the same.
Define mean.
The value obtained by dividing the sum of several quantities by their number.
An average.
Define median.
The middle number in a given sequence of numbers.
Define mode.
The value that occurs most frequently in a given set of data.
Define conclusion.
A very brief summary of the results and their implications.
Define scientific method.
A process of observation, measurement and analysis.
Designed to test formulated hypotheses.
Helps us to - explain phenomena
- predict changes in a system
What do hypothesises lead to?
Predictions that are ACCEPTED or REJECTED based on the investigation findings.
Features of a sound hypothesis.
Based on observations and prior knowledge of the system
Offers an explanation for an observation
Refers to only ONE independent variable
Written as a definitive statement and NOT a question
Testable by experimentation
Leads to predictions about the system
Features of a sound method.
Tests the validity of the hypothesis
Repeatable
Includes a control which DOES NOT receive a treatment
All variables are controlled where possible
Includes a dependent and independent variable
Only the independent variable is changed between treatment groups
Define null hypothesis.
A hypothesis of no difference or effect
For every hypothesis, there is a corresponding null hypothesis
What does a null hypothesis allow?
A hypothesis to be tested using statistical tests
If the hypothesis is accepted, then the null hypothesis is rejected
Describe qualitative data?
Non-numerical and descriptive
Eg: sex, colour, presence/absence of a feature
Describe quantitative data.
Characteristics for which measurements or counts can be made
Eg: height, weight, number
Can be - Continuous (number of offspring)
- Discontinuous (height of offspring in a family)
What graphs are used to display qualitative data?
Bar and column graphs
What are bar/column graphs used for?
Plotting data that is non-numerical or discrete for at least one variable (i.e. they are grouped into categories)
What graphs are used to display quantitative data?
Line graphs
Rules for line graphs.
Data must be continuous for BOTH variables
–The dependent variable is usually the biological response
–The independent variable is often time or experimental treatment
OBVIOUS trend: draw a line of best fit
Important fluctuations: connect data points
–Lines may be drawn with standard error or confidence intervals
What are descriptive statistics used for?
Summarising data
Providing information about its distribution and spread
Examples of some basic descriptive statistics.
Mean Median Mode Variance Standard deviation Standard error Confidence interval
What are the mean, median and mode used for?
Identifying the central tendency of a data set
What are the variance, standard deviation, standard error and confidence interval used for?
Quantifying the variability around the central value and evaluating the reliability of the mean
What are line graphs used for?
Plotting continuous data in which the independent variable DIRECTLY affects the dependent variable
Define measurement error.
The difference between a measured value of quantity and it’s true value.
Define confidence interval?
Expresses the degree of uncertainty associated with a sample. It is an interval estimate combined with a probability statement.
Define instrument accuracy.
A measure of the instrument’s veracity (accuracy)
Define limitation of experimental design.
Every experiment has some limitation
Eg: time, cost
What are the 3 basic transformations commonly performed?
Percentage
Rate
Average
