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For example as a result of measuring the density of kerosene 3

magnitudes (ρ , ρ , ρ ) are received.
3
1
2

Average magnitude of measured parameter:
n
 ρ
i 1 i
ρ m avr  . (6.2)
n

Absolute error of the certain (і-th) measurement:

Δρ = |ρ m avr – ρ |. (6.3)
і
і

Average absolute error Δρ m avr is average arithmetic of absolute

errors of several measurements:
n
  ρ
i 1 i
ρ m avr  . (6.4)
n

Relative error is the ratio of the average absolute error Δρ m avr
to the average magnitude of the measured parameter ρ m avr :
 ρ
  m avr . (6.5)
ρ m avr

The rules which should be followed while using

areometers and densimeters

1). To avoid the losses of time for picking up the necessary areometer
at first the liquid density has to be determined by means of the

3
areometer with more wide scale (for example from 1.0 to 1.8 g/cm )
and only after this by means of the areometer with narrow scale (for

3
example from 1.2 to 1.4 g/cm ).
2). Avoid areometer turning round and touching the walls of the

measuring cylinder while determining the liquid density by the scale
of areometer.
3). Taking areometer readings is conducted by the upper mark of
the scale at the level of liquid surface (by the upper surface of

meniscus).

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