reliability, accuracy, precision Flashcards
define accurate
how close measurement is to the true/ accepted value
define reliability
how small the variations btw values are
define precise
how close measurement of the same value are to each other
define measurement error
diff btw measured value and true value
define true value
value you get in an ideal experiment
note: accuracy is between true value
precision is between results
define repeatability
if you can get same result when doing the same experiment again
define reproducibility
if you can get same results when doing a diff experiment
define validity
-experiment is fair or not
-have controlled variables
define range
max and minimum values of the variables
define anomaly
value which is outside of general pattern of values
define dependent variables
-what you measure
-x axis
-left of table
define independent variable
-what you change
-y axis
-right of table
how to increase reliability
-take minimum 3 readings and find mean
-repeat experiment and find mean value
-make sure rest of variables are controlled
Phy:
-use equipment properly
-repeat experiment 3 times
-follow the method closely
define control variables
-what you keep the same
-helps with comparison
-for validity
how to increase accuracy
-use proper apparatus
-use correct method when using apparatus
-repeat readings 3 times
-take readings at smaller intervals and find mean
Phy:
-find mean time
how to increase precision
-like more decimal place (eg. 3.2 is more precise than 3)
-use proper apparatus (more suitable ones)
-raw value is more precise than mean value
note: same decimal place in table & units in heading
what is amount used for
-time
-energy
-money
what word do you use for countable things
number
what word do you use for liquid
-volume
-ml
-cm^3
what word do you use for like measuring solute is solvent (eg. salt in water)
-concentration
-mol/ dm^3
-%
what word do you use for measure mass
-mass
-kg
-g
percentage change formula
final - initial
——————- X 100%
initial
rules for drawing graphs
-independent variable - x axis
-dependent variable - y axis
-x & y axis must be labeled with units
-draw the line of best fit- curve or straight
-scale must be even on both side
-use up more than half of the paper on both sides ( x & y)
-plot using “x” - has to be in middle of 4 boxes
how do you calculate gradient
-rise over run (hypothenuse)
-in 3 sf
why is repeating and finding mean reliable
identifies anomalies
why does a reaction stop
-the reactants are used up
