Chapter 1.5 Uncertainty in Measurement

Question 1

The 2 kinds of numbers encountered in science are

Answer 1

1. EXACT NUMBERS ( defined values, number of things, the number 1 in any conversion, numbers derived from counting)
2. INEXACT NUMBERS ( numbers obtained from MEASUREMENTS, they always have some uncertainty to possible equipment or human error

Question 2

2 terms used in discussing the uncertainty of measurement

Answer 2

1. Precision

2. Accuracy

Question 3

PRECISION

Answer 3

Is a measure of how closely individual measurements agree with one another

Question 4

ACCURACY

Answer 4

refers to how closely individual measurements agree with the correct or “true” value

Question 5

STANDARD DEVIATION

Answer 5

The precision of measurements is often expressed in terms of STANDARD DEVIATION .
It reflects how much the individual measurements differ from the average

Question 6

What notation is used to express the magnitude of your uncertainty of measurement

Answer 6

±

Question 7

SIGNIFICANT FIGURES

Answer 7

Are all the digits of a measured quantity, including the uncertain ones

Question 8

Identify Significant digits

Answer 8

1. All non zero numbers
2. All zeros between nonzero numbers( 1005=4)
3. Zeros at the the end of a number with a decimal point (0.0200=3)

Question 9

non- Significant figures

Answer 9

1. zeros at the beginning of a number ((0.0200=3)

2. Zeros at the end of a number without a decimal point 30=1

Question 10

Addition and subtraction of Significant figures

Answer 10

The result has the same DECIMAL PLACES as the the measurement with the FEWEST decimal places

Question 11

Multiplication and Division

Answer 11

measurement with the FEWEST SIGNIFICANT FIGURES