Which of the following statements about random errors is incorrect?
A. Random error is caused by many unmeasurable errors that can affect the measurement result.
B. Random error is always too large or too small.
C. Random error conforms to normal distribution.
D. Random errors not only affect the accuracy of the measurement results, but also significantly affect the precision of the measurement results.
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Which of the calculation about significant figures is incorrect?
A. 0.03050 has 4 significant digits.
B. 12.050 has 5 significant digits.
C. pH = 5.25 has 3 significant digits.
D. 7.2×10–5 has 2 significant digits.
Which of the following statements about errors is wrong?
A. Uncalibrated instrument will cause errors
B. Impure reagents will cause measurement errors
C. System errors can be eliminated by improving test methods
D. Random errors can be eliminated by improving test methods
All errors can be eliminated by the proper methods.
Standard deviation can better reflect the closeness of analysis results.
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