Research methods- scientific methodologies Flashcards
what are the general principles of scientific investigations?
identifying a topic on interest
finding out what has already been learnt
formulating a hypothesis/ null hyothesis that can be tested
designing and carrying out an experiment to test the hypothesis
designing the investigation
analysing the results and drawing conclusions
planing further research to fill gaps in existing knowledge or develop the study further
what must be considered when designing an investigation?
location of sampling sites
number of samples
size of samples
standardised technique
timing of sampling
statistical analysis to assess staistical significance
why is careful planning needed for studies?
to ensure data collected can be used to conclude whther a hypothesis should be accepted or rejected
so that statistical significance of the results can be assesed
what is it rarely possible to do with data collection?
collect all the data that exists about a particular issue
what is more usual with data collection then collecting all samples?
collect sub-samples and use these to estimate the full situation
how will subsamples produce a reliable conclsuion?
will only do so if the sub smaples are are representative
what can make sub-samples more representative?
location
timing
size
number
what should be done to test the reliability of the method?
a preliminary study
what must you do if data is not being collected at a single location?
then decisions will jave to be made about the positioning of the smapling sites
what is it essential to do when selecting smapling loations?
aviod the introduction of bias caused by deliberate selection of locations for convinience or to support or dimiss a hypothesis
how can the introduction of bias be avioded?
by simple random or systematic sampling
how can random sampling be done?
if the study area is a regular shape then a grid can be laid out and the coordinates of sampling sites selected using random numbers
if the study area is an irregular shape then all possible sampling sites can be numbered and selected using a random number generator
what is systematic sampling?
involves samples being taken using a chosen interval between samples
not based on choices made using observable differences in the study area
what types of systematic sampling can be done?
along a line trasnect- only things on the line
continuous belt transect- every square sampled using quadrat anything in or very close to the belt
interuped belt transect- sampling locations at regular intervals
what should the distance between sample locations be with systematic sampling?
should be selected to detected variable data (changes that happen)
don’t want it too be to small and collect unneccsary data
can be determined with a premininary study
why mustsampling timing be considered?
if the factor that is being measured changes with time then it will be necessary to sample on different occasions to produce a mean result that represents the ‘typical’ value or identify trends/ changes
what is the ideal time left between taking samples?
depends on the rate at which values in that area change
can be determined with a preliminary study
what variables will be sampled on a long term timescale?
popualtion changes (tigers)
area of rainforest
Atmospheric CO2 level
what variables for samples will be measured on a seasonal timesclae?
presnece of migratory species
population of annual wild flowers
temperature
atmospheric CO2 level
river level
what variables will be measured on a diurnal scale? (24hrs)
light levels
temperature
Atmopsheric CO2 levels
what variables will be measured on minute to weekly scale? (Enviro)
weather related changes
flying insect activity
wind velocity
temperature
what are other variables will be measured short term?
road noise levels
how does sample size affect an investigation?
if the variable being measured is not homogenou then larger samples are more likely to produce representative results
how can a sample for an investigation be decided?
be a preliminary study
why can you just take one sample when investigating something?
may not be representative as there may be variability between samples
what is the benefit of collecting multiple samples in an investigtion?
multiple samples will help to eliminate the effect of variability
how many samples should you collect for an investigation?
at least 10
what is needed to produce a representative mean?
depends on upon the degree of scatter around the mean
how can the degree of scatter be measured from a data set?
assessed by calculating the standard deviation
why must you use a standardisation of techniques?
to allow a comparison of the results that are collected at different times in different locations or by different researchers they must all be collected in the same way
what must be done with other vaiables that may affect the results?
must either be controlled or monitored to assess their effects
