Paper 5 Flashcards
what does standard deviation do
evaluates reliability of the data by showing spread of data around the mean
the smaller the value of s the more reliable the data as they are more closely related to the mean
what does standard error show
shows reliability of mean
the smaller the value of Sm the more reliable the mean is
how is 95% confidence limit calculated and what are they used for
plus and minus 2sm
or plus and minus tsm
they are used to plot error bars to show if difference between 2 means is significant or not
if they overlap then diff is of no significance
what is t test used for
to show if difference between 2 means is significant or due to chance
how do u calculate degree of freedom for t test
n1+n2-2
how is t test used
probability table at 0.05 at row of calculated degree of freedom to determine critical value t
if calculated t value is greater than critical value then there is significant difference
what is the critical value
value under probability 0.05
sometimes known as 95% confidence level
what is chi squared test used for
tests for differences between obtained observed and expected frequencies of nominal data in genetics and ecology
what is hardy weinberg used for
estimates allele frequencies in a population and chances of passing on a particular genotype
pearson’s linear correlation
tests for correlation between 2 sets of normally distributed data
spearman’s rank correlation
tests for correlation between 2 sets of normally distributed data
the closer the value to 1 the stronger the correlation
peterson or lincoln index
measures species richness and evenness from number of diff species in habitat
how are immobilized enzymes made
add sodium alginate using dropper in calcium chloride solution and mix
why is chi squared used
data is categoric
variables and how they are controlled
humidity:by humidifier
temp:temp controlled room or thermostatically controlled WB
PH:using buffer solution
CO2:soda lime to absorb/CO2 meter/sodium hydrogen carbonate as source
light intensity:by fixing bulb at distances
how is a haemocytometer used
calculate vol of smaple
(lengthxwidthxheight)
divide number of(object/sample ex sperm)by volume
+method of converting to cm
count number of object(sperm)filly inside square
include those touching the line
dilution of sample
repeat in diff fields of vision to calculate a mean
explain how light microscope is used to calculate actual diameter of object
using an eye piece graticule
calibrate using stage micrometer
use formula: number of stage micrometer divisions x value of one micrometer division ➗ number of eye piece units
describe how student could dilute 250mmoldm3 sol to make 100cm3 by reducing conc by 50mmol each time
simple dilution c1v1=c2v2 200=20cm3 from water and 80cm3 stock 150=40cm3 water and 60cm3 stock 100=60cm3 water and 40cm3 stock 50=80cm3 water and 20cm3 stock measure vol using measuring cylinder and stir
systemic sampling investigation
transect lines with starting point at beginning of(area)
use measuring tape to measure 10m away from area
get quadrats of known size and dimensions
place quadrats 2m apart
identify each species in quadrats using pictures
calculate species frequency
calculate% coverage
replicate transect lines at diff edges from area parallel
to each other
risk of getting injured so wear thick gloves and boots
risk of getting lost so stay with group
mark release recapture
catch as many individuals as possible
each is marked in a way that wont affect its survival
marked are counted and returned back to their habitat to mix
after a large time another sample is collected
no of marked and unmarked are counted
estimate no of population:
no of caught in first sample x number caught in 2nd sample/no marked in second sample
when is random sampling used
when area looks uniform and there is no clear pattern to the way species are distributed
state what is needed to calculate simpons index of diveristy
count number of all species
