Transcript Determinate Error

GROUP MEMBERS
NOR ADILA RAMLEE
NOR HIDAYAH OTHMAN
NUR FARIZAH BINTI JABARULLAH
BASIC STATISTIC
TYPE OF ERROR
DETERMINATE
ERRORS
SIGNIFICANT
FIGURES
INDETERMINATE
(RANDOM
ERROR)
Determinate Error
Errors that occur because
of some reasons and have
specific values
Characteristic of determinate errors :
cause of error is known
consistency, that is values are almost the
same
one- sided, example having the same sign
will give effect to accuracy of the method
can be corrected and avoided
Personal
errors
Errors of
the
reagent
Types of
determinate
or systematic
errors
Method
errors
Instrument
al errors
Personal Errors
caused by carelessness or not
using the right techniques by the
operators
example : recording wrong burette
reading as 29.38mL,wheares the
correct reading is 29.35mL.To
avoid this error is by reading the
volume correctly
Instrumental errors
The faulty equipments, uncalibrated weight
and glassware used may caused instrumental
errors
example: using instruments that are not
calibrated and this can be corrected by
calibrating the instruments before using
Method Errors
Caused by nature of the methods used. This error cannot be omitted
By running the experiments several times. It can be recognized and
Corrected by calculations or by changing to a different methods or
Techniques.
This types of error is present in volumetric analysis that is caused
by reagent volume. An excess of volume used as compared to theory
will result in the change colours
Example: mistakes made in determining end point caused by
coprecipitation
Errors of the reagent
This error will occur if the reagents
used are not pure. Correction is
made by using reagent or by doing
back-titration
Indeterminate or random errors
cause of error is unknown
spreads randomly around the middle value
usually small
have effects on precision of measurement
cannot be corrected
Example of indeterminate
errors is the change of humidity
and temperature in the balance
room that cannot be controlled
Significant figures
Digits that are known to be certain plus one
digit that is uncertain
The zero value is significant if it is part of
the numbers ; it is not a significant figure if
used to show magnitude or to locate the
decimal point
The position of decimal point has no
relation with significant figures
Step in writing significant figure
rounding off
addition and subtraction operation
multiplication and division operation
Exponential
logarithms and antilogarithms operation
Rounding off
If the last digit to be removed is greater than 5, add one to the
last digit. EXAMPLE:
22.486
22.49
If the last digit to be removed is smaller than 5, then the second
last digit does not change. EXAMPLE:
31.392
31.39
If the last digit is 5 and the second last digit is an even number,
thus the second last digit does not change. EXAMPLE:
73.385
73.38
If the last digit is 5 and the second last digit is an odd number,
thus add one to the last digit. EXAMPLE:
63.275
63.28
Addition and subtraction operation
The number of digits to the right of decimal point in the
operation of addition/subtraction should remain.
The answers to this operation has a value with the least
decimal point.
EXAMPLE: Give the answer for the following operation to the
maximum number of significant figures
43.7
4.941
+ 13.13
61.771
61.8
# the answer is therefore 61.8 based on the key
number(43.7)
Multiplication and division operation
The number of significant figures in this operation
should be the same as the number with the least
significant figure in the data
EXAMPLE: give the correct answer for the
following operation to the maximum number of
significant figures
1.0923 X 2.07
Solution:
1.0923 X 2.07 = 2.261061
2.26
# the correct answer is therefore 2.26 based on
the key number (2.07)
Exponential
The exponential can be written as follows.
EXAMPLE:
0.000250
2.50 X 10−4
Logarithms and antilogarithms operation
Log ( 3. 1201 )
mantissa
characteristic
The number of significant figures on the right of the decimal
point of the log result is the sum of the significant figures in
mantissa and characteristic
EXAMPLE: what is the value of log 2.1 X 10^6 , log 1.8 X
10−5 and antilog 10.8 with the correct significant figures
Solution:
log (2.1 X 10^6) = 6.32
log (1.8 X 10−5) = -4.74
Antilog 10.8 = 6 X 10^10