Maths skills

Units and abbreviation

km-m-cm-mm-micrometers-nanometers

left to right - x1000, x 100, x 10 , x 1000, x 1000

right to left- ÷1000, ÷100, ÷10, ÷1000, ÷ 1000

kilometer

metre

centimetre

millimeter

micrometer

nanometer

10^3=1000m

1m

10^-2=0.01m

10^-3=0.001m

10^-6=0.000001m

10^-9=0.000000001m

Graph plotting

* x-axis- on the bottom, the variable that you are changing: Independent
* y axis-top right , shows variable measuring: dependant variable
* dots jointed straight line
* no extend beyond data points

Bar chart

plotted when the IV is not numerical, has no numbers but has categories bars that do not touch

histogram

show frequency distribution with continuous data/measurement for IV, bars can touch, data is grouped into classes

Line graph

show relationship between 2 variables indicate the effect of IV on the DV

ecological pyramid

* different organisms in food relationships/feeding levels
* plants producers base
* consumers are symmetrical
* width of bar proportional to organisms’ biomass energy at each level

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scatter graph

plot them identify if there is a pattern or correlation

calculate percentage

amount/total x 100

percentage increase

value after increasing - value before increasing/ value before increasing

percentage decrease

value before increasing - value after increasing/ value before increasing

standard deviation

* spread of data around the mean

\+/- 2 SD five us the confidence to say that 95% of all values are within the range

* if the SD is small spread of data around the data more reliable
* large then the large spread of data less reliable
* SD does not overlap there is a significant difference between 2 data sets
* SD overlap there is no significant difference