Question

If the fractional part of a positive number to be dropped is equal to or greater than one-half, the preceding digit will be increased by one. If the fractional part of a negative number to be dropped is greater than one-half, the preceding digit will be decreased by one. When cloud height and visibility values are halfway or less between two reportable values, report the lower value. True or False?

Answer 1

The question is about understanding significant digits in measurements, where all nonzero digits, embedded zeros, and trailing zeros with a decimal point are significant. This precision communicates the certainty of the measurement process.

Step-by-step explanation:

When reporting measurements, it is important to understand which digits are significant and thereby convey the precision of the measurement.

Understanding Significant Digits

All nonzero digits are significant. Zeros present different cases:

• Leading zeros are not significant as they merely indicate the position of the decimal.
• Embedded zeros (between nonzero digits) are significant.

The significance of trailing zeros depends on the presence of a decimal point. Without a decimal point, they may simply be place-holders. However, with a decimal point, they are always significant.

Rule 5 particularly emphasizes the importance of trailing zeros in a decimal number: "Trailing zeros in a number with a decimal point are significant." This applies regardless of whether the zeros occur before or after the decimal point.

Practical Measurement Example

If a distance is measured as 54.5 mm, this measurement has three significant figures, two exact digits, and one estimated digit, which is the least significant digit. This level of precision must be reported accurately to convey the exactness of the measurement.